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1 //! The webview renderer for [`makeover_layout`].
2 //!
3 //! <!-- wiki: makeover-webview -->
4 //!
5 //! # The renderer that needs no palette
6 //!
7 //! `makeover-immediate` and `makeover-tui` both take a `Palette`, because egui
8 //! and a terminal need an actual colour before they can put anything on
9 //! screen. A webview does not: `var(--surface-raised)` *is* the late binding,
10 //! and the browser resolves it against whatever `themes.js` last wrote onto
11 //! `:root`.
12 //!
13 //! So this crate emits text naming intents, and never learns a colour. It is
14 //! the deferral rule with no adapter in the way, and it is why the webview was
15 //! always the wrong renderer to derive a vocabulary from: it can express
16 //! anything, so it never pushes back.
17 //!
18 //! # Phase A: the stylesheet
19 //!
20 //! This module emits component CSS and no markup, deliberately. GoingsOn has
21 //! 145 `innerHTML` sites and Balanced Breakfast 175 `createElement` sites, so
22 //! moving markup is a migration where adopting a generated stylesheet is not.
23 //! The apps keep every line of their markup and gain the classes.
24 //!
25 //! It is not a deletion either, which this header claimed until the measurement
26 //! came in. Adoption across goingson removed 49 declarations net and *added* 25
27 //! lines: a rule loses its depth declarations and gains a variant selector next
28 //! to it, so the file stays the same size. What phase A moves is where depth is
29 //! defined, not how much CSS exists. Numbers and method in the wiki note under
30 //! "The deletion test, run".
31 //!
32 //! The bevel properties are byte-identical to what both apps already
33 //! hand-write, which is asserted below.
34 //!
35 //! # Phase B: the markup, one description at a time
36 //!
37 //! [`form`] renders [`makeover_layout::Field`], which is the half of phase B
38 //! whose description is settled. It emits strings, because both apps
39 //! interpolate their fields into larger string-built forms and returning nodes
40 //! would rewrite those too. It owns its own escaping, on the reasoning in that
41 //! module: a Rust encoder can cover element text and attribute values with one
42 //! function, where the apps need four and have to choose correctly at every
43 //! call site.
44 //!
45 //! [`facet`] renders `makeover_layout::Facet`: a dimension a set is narrowed by,
46 //! and the one phase-B emitter whose markup an app is not keeping, because the
47 //! markup it replaces was two mechanisms rather than one. A tag's selection and
48 //! a tag's browse position were separate state on MNW's discover page, which is
49 //! why every filter row there carries a tick box *and* a chevron; one gesture
50 //! doing both is what lets the second one go.
51 //!
52 //! [`list`] is the other half: column tracks, the narrowing rules, and the cell
53 //! containers a row is made of. It stops at the cell boundary and does not
54 //! render what goes inside one, on the reasoning in that module. So phase B is
55 //! now the frame around content in both directions, and what an app still owns
56 //! is the content itself.
57 //!
58 //! # What phase A settled, and what it costs
59 //!
60 //! Decided 2026-07-29 against goingson's `styles.css` rather than against a
61 //! component list. The useful finding there was that `.btn` (line 644),
62 //! `.card` (768) and `.tag, .badge` (882) each hand-write the same
63 //! composition, so three quarters of phase A is one rule with several names.
64 //!
65 //! Two of the four decisions change how goingson looks, and adoption should
66 //! not be described as a pure deletion:
67 //!
68 //! - **Pressed carries its fill.** [`interactive_rules`] emits
69 //! [`Depth::pressed`] whole. goingson presses to `--surface-sunken` today and
70 //! will press to `--surface-well`, and hovers to `--surface-overlay` today
71 //! and will hover to `--hover-surface`. Since `surface-well` inverts by theme
72 //! where `surface-sunken` does not, a dark theme presses *lighter* than it
73 //! hovers. That falls out of `makeover`'s own derivation, which says outright
74 //! that `surface-sunken` cannot serve as a well, so if it reads wrong the
75 //! answer is there and not here.
76 //! - **Badges go flat.** See [`token_rules`].
77 //!
78 //! The other two: the progress trough is renderer-local and the scrollbar
79 //! track was dropped ([`component_rules`]), and no class prefix ships by
80 //! default, so adoption means deleting the app's hand-written rule in the same
81 //! commit that adds the generated one. `.card`, `.badge` and the tab classes
82 //! all already exist in goingson, and while both rules exist the cascade order
83 //! decides which wins. That is the one real risk in adopting this, and it is
84 //! why the migration lands per component rather than in one commit.
85 //!
86 //! # 0.10.0: the states this crate used to leave to its consumers
87 //!
88 //! [`interactive_rules`] emitted hover and pressed and stopped, because
89 //! `makeover-layout` modelled no interaction state. Focus and disabled were
90 //! therefore unsayable, and every app completed the primitive from outside the
91 //! only way that works: by out-specifying a rule it does not own. goingson
92 //! carries 19 such rules and the MNW server 21, and the three focus rings do
93 //! not match each other.
94 //!
95 //! That also blocked the cascade-layer work outright. An app that declares
96 //! `@layer` puts its own rules in a named layer, and unlayered declarations
97 //! outrank every named layer regardless of specificity, so all of those
98 //! overrides lose in the commit that adopts layers. They cannot simply be
99 //! deleted, because they are the only thing supplying the missing states.
100 //! Emitting the states here is what turns that adoption into a deletion.
101 //!
102 //! Four states now, in emission order, and the order is load-bearing: they are
103 //! all specificity (0,2,0), so disabled beats hover by coming last and by
104 //! nothing else. Nothing here reaches for `:not(:disabled)`, which would raise
105 //! a selector this crate will shortly be wrapping in its own layer.
106 //!
107 //! Hover additionally sits inside a capability query now. `makeover-touch`
108 //! answers whether a fingertip has hover and `makeover-geometry` spells the
109 //! condition; this crate asks and does not decide. goingson's section 60 exists
110 //! solely to take the hover state back on touch, which is a fight it should
111 //! never have been handed.
112 //!
113 //! # 0.11.0: the layer contract
114 //!
115 //! [`stylesheet`] emits into the `makeover` cascade layer ([`CSS_LAYER`], which
116 //! lives in `makeover-geometry` because that is the one crate every CSS emitter
117 //! in the family already depends on). `makeover-geometry` 0.6.0 does the same
118 //! for `geometry.css`.
119 //!
120 //! The cascade resolves origin and importance, then layer, then specificity,
121 //! then source order, and **unlayered normal declarations outrank every named
122 //! layer**. So before this, an app that declared `@layer base, components,
123 //! responsive` put every rule it owns into a named layer and lost all of them to
124 //! this unlayered file, regardless of specificity and regardless of loading
125 //! last. Nothing errors when that happens: the CSS is valid, the minifier is
126 //! happy, and buttons and badges look subtly wrong.
127 //!
128 //! That is why the layer belongs here rather than in each app. An app cannot fix
129 //! it from its own stylesheet, because the fix is to layer the file it does not
130 //! own.
131 //!
132 //! **What it flips**, and the reason each app wants a look when it bumps the
133 //! pin: a generated rule that currently beats an app rule by being more specific
134 //! stops beating it. The direction is always "the app wins", which is what the
135 //! apps already assume, but a hand-written rule an app thought was dead can come
136 //! back to life.
137 //!
138 //! An app should declare the order once, or the layer's position is decided by
139 //! whichever generated file the browser happens to see first:
140 //!
141 //! ```css
142 //! @layer makeover, base, components, responsive;
143 //! ```
144 //!
145 //! [`in_css_layer`] is re-exported for an app that assembles its own stylesheet
146 //! from this crate's pieces. goingson builds `tables.css` in its own `build.rs`
147 //! out of [`list::narrowing_css`] and [`list::grid_template_columns`], and those
148 //! rules are as generated as the ones here, so they belong in the same layer and
149 //! this crate cannot put them there on the app's behalf.
150 //!
151 //! # 0.12.0: the ring gets its own width
152 //!
153 //! [`focus_rule`] reused [`Emit::border_width`] and emitted a 1px ring. That was
154 //! an implementation convenience dressed as consistency with the invalid-field
155 //! ring: a bevel and a focus indicator answer different questions, and only one
156 //! of them has to be noticed from across a desk.
157 //!
158 //! Caught while adopting 0.11.0 into goingson, by the check the adoption tasks
159 //! ask for. Every consumer had already written its own ring and all three chose
160 //! at least 2px: the MNW server 2px across 10 rules, Balanced Breakfast 2px,
161 //! goingson 2px on three rules and 3px on the one covering twelve selectors. The
162 //! design system was the only thing in the tree saying 1px, so deleting the app
163 //! rules in favour of it would have thinned the focus indicator everywhere.
164 //!
165 //! [`Emit::focus_width`] now carries it, defaulting to `2px`, and the offset is
166 //! the same magnitude with its sign off the depth. Both values are the measured
167 //! consensus rather than a new opinion.
168 //!
169 //! # 0.57.0: a suggestion's second line, in place of a reason it cannot be picked
170 //!
171 //! `1fcf2e9b`, ruled by Max 2026-08-21. `Outcome::Suggestions` now carries
172 //! `Candidate` rather than `Choice`, and a candidate has no `unavailable`: a
173 //! suggestion that cannot be picked is a row a route should not have offered.
174 //! What it has instead is a `detail`, the line that tells it from a row reading
175 //! the same -- "Format" under audio, software, writing and video.
176 //!
177 //! So `.form-suggestion-why` is gone and `.form-suggestion-detail` is here, and
178 //! the difference is not only the name. `why` was drawn in the disabled token,
179 //! which said the row was refusing. A detail orients rather than refuses, so it
180 //! is `--content-muted`, which is what every other secondary line in this crate
181 //! reads as.
182 //!
183 //! No consumer is affected: the only emitter is `quasi-webview`, which moves in
184 //! the same cascade.
185 //!
186 //! # 0.56.0: an interval, as the group MNW already wrote by hand
187 //!
188 //! [`makeover_layout::FieldKind::Interval`] emits a `role="group"` named by the
189 //! field's label, holding one `<input type="number">` per end. That is not a
190 //! shape invented here: MNW's discover sidebar has a `role="group"` with
191 //! `aria-labelledby` over `min_price` and `max_price` today, written by hand
192 //! because nothing in the description could say the two boxes were one
193 //! question. The markup is what the measurement found, and this emits it.
194 //!
195 //! - **The group carries the error and the descriptions**, on the split
196 //! [`makeover_layout::FieldKind::Radio`] already uses here: what is wrong is
197 //! the answer, and a crossed interval is not the fault of either end.
198 //! - **Both boxes take the whole extent.** `min`, `max` and `step` describe the
199 //! axis, so they are written twice. The crossing rule is not emitted, because
200 //! HTML has no attribute for it and the description does not carry it: it
201 //! comes back as an error on the group, like every other refusal.
202 //! - **Which end is which is `aria-label` and nothing more.** The description
203 //! states direction structurally, by which member holds which name, and never
204 //! in words. Visible Min and Max captions are a page's own and reach the
205 //! group through [`form::Filling::trailing`].
206 //!
207 //! [`form::Value::Between`] is the second value. A separator inside one string
208 //! would have made this crate the owner of a delimiter that either end could
209 //! contain.
210 //!
211 //! # 0.55.0: a number's unit, as adjacent text
212 //!
213 //! `makeover-layout` 0.33.0's `Field::unit`. HTML has no unit attribute and
214 //! inventing one would be markup nothing reads, so it is a `<span>` after the
215 //! control -- and it is named in `aria-describedby` rather than left as
216 //! decoration, because a number and what it is measured in are one fact and
217 //! reading the first without the second is reading it wrong.
218 //!
219 //! This is the renderer the member costs something. egui already had somewhere
220 //! better than the label to put a unit; here the two placements are equally
221 //! adjacent, and what is bought is that the unit is a value a consumer can read
222 //! back rather than a suffix on a label it would have to parse.
223 //!
224 //! # 0.54.0: a curve this renderer can carry, and one it cannot
225 //!
226 //! `makeover-layout` 0.32.0's `Curve`. A range takes its granularity from the
227 //! curve now (`Field::curve.step()`), every other kind keeps `Field::step`, and
228 //! `Curve::Linear` emits exactly what it emitted before.
229 //!
230 //! **A constant-ratio curve still emits a linear track, and that is a
231 //! shortfall rather than a decision.** HTML has no logarithmic range input, so
232 //! honouring one here means either shipping JS that maps the thumb position to
233 //! a value -- renderer-side app code, which is the thing this stack exists to
234 //! delete -- or changing what the control submits from a value to a fraction,
235 //! and then something has to map it on the way back in. That something is not
236 //! this crate: the MNW server reads these forms with its own handlers, so a
237 //! fraction arriving where a value is expected would be silent. Filed rather
238 //! than guessed at.
239 //!
240 //! What is not lost: the extent, the granularity, and the value's own units.
241 //! What is lost is resolution at the small end, which is exactly the reason an
242 //! app asked for a ratio in the first place. No consumer is affected today --
243 //! every described range on this path is linear.
244 //!
245 //! # 0.52.0: a markdown field gets the preview it was permitted
246 //!
247 //! 0.50.0 marked a [`makeover_layout::FieldKind::Rich`] field with
248 //! `data-format="markdown"` and stopped there, and nothing read the mark: no
249 //! rule, no markup, no selector anywhere in the tree. So a described editor was
250 //! a plain textarea carrying an attribute, and MNW converting its four
251 //! hand-written section editors onto the member would have *lost* the
252 //! Write/Preview pair one of them already has. A permission taken and not spent
253 //! turns every conversion into a regression.
254 //!
255 //! [`form::editor_rules`] and the chrome beside it are the spending. The pair is
256 //! a segmented control, so it takes the depth, the focus ring and the chosen
257 //! state from rules that already existed; the preview pane is a well, because it
258 //! stands where the control stood. Both are gated on the attribute rather than
259 //! on a class, which is what the attribute was for.
260 //!
261 //! **This crate still renders no markdown.** The pane arrives empty and is
262 //! filled by whatever binds the editor, which is where the host's sanitiser
263 //! already is. A converter here would have moved that guarantee into a crate
264 //! with no view of the host's content-security posture.
265 //!
266 //! # 0.47.0: a range, a chooser's ghost text, and an option that cannot be
267 //! picked yet
268 //!
269 //! `makeover-layout` 0.28.0's three form findings, all of them cheap here and
270 //! none of them cheap in the app that found them.
271 //!
272 //! - `FieldKind::Range` emits `<input type="range">`, and `Field::step` emits
273 //! `step`. The step is emitted only when the description carries one: the
274 //! browser's own default is `step="1"`, which is what a description means by
275 //! saying nothing, and is also what turns a 0-to-1 threshold into a
276 //! two-position control.
277 //! - A select with nothing chosen emits a disabled, selected, valueless first
278 //! option carrying `Field::placeholder`. HTML has no placeholder attribute on
279 //! `<select>`; this is the idiom, and `required` keeps working through it
280 //! because the option's value is empty.
281 //! - `Choice::unavailable` emits `disabled` plus the reason. Where it goes
282 //! differs by control and the difference is forced: a radio group gets a
283 //! `.form-option-reason` span beside the label, and a `<select>` option has
284 //! room for no element at all, so the reason runs into its text.
285 //!
286 //! # 0.25.0: a cell says what it holds
287 //!
288 //! 0.23.0 gave a table its layout and left every cell the same. One `.cell`
289 //! carried the whole thing, so a cell holding text and a cell holding a button
290 //! were one class and one content colour, and a control in a cell was painted
291 //! as text. That is the drift [`RowPart::intent`](makeover_layout::RowPart)
292 //! has prevented for list rows since 0.2.0 and prevented for nothing here.
293 //!
294 //! makeover-layout 0.14.0's [`CellPart`](makeover_layout::CellPart) names the
295 //! four things a cell holds, and [`table_rules`] turns them into
296 //! `.cell-value`, `.cell-tokens`, `.cell-actions` and `.cell-link`. Only the
297 //! first takes a colour: a token carries its own tone, an action is a control
298 //! rather than text, and a link takes the action colour from the anchor it is.
299 //!
300 //! The colour going on `.cell-value` rather than on `.cell` is the fix rather
301 //! than an implementation detail. On the container it cascades into the parts
302 //! that are not text, which is the bug said in one rule.
303 //!
304 //! [`list::Cell::part`] is `Option<CellPart>` here, where it was
305 //! `Option<RowPart>`. A table cell borrowing the list row's vocabulary was the
306 //! drift with a type on it: the two answer different questions, and only one of
307 //! them was ever about a cell.
308 //!
309 //! # 0.23.0: a table lays itself out, and a row shows its controls
310 //!
311 //! Three things a description could say and this renderer had no rule for,
312 //! found together by rendering the MNW server's SSH-keys settings tab through
313 //! `quasi` and preferring the hand-written Askama original.
314 //!
315 //! **A table had no layout at all.** [`list::narrowing_css`] emits the track
316 //! list, and it has to be called with the columns, so it works where the
317 //! columns are known at build time: goingson builds `tables.css` in its own
318 //! `build.rs` and is untouched. A table a description produced knows its
319 //! columns at render time, and the rules would have had to travel with the
320 //! markup: a `<style>` element per table, which needs `style-src
321 //! 'unsafe-inline'` that the MNW server is working to drop, or the head, which
322 //! an htmx fragment swap does not carry. [`table_rules`] lays a table out with
323 //! `display: table` instead, which aligns columns across rows knowing nothing
324 //! about how many there are. [`Priority`](makeover_layout::Priority) hiding
325 //! moves from a generated rule per dropped column to one rule per drop class,
326 //! and [`list::column_classes`] is what puts those classes on a cell. A header
327 //! row emitted by a renderer's own code should call it too, or the header and
328 //! the body disagree about which column just dropped.
329 //!
330 //! **A destructive button had nowhere for its tone to land.** `.button` carried
331 //! no tone, on the reading that a control's colour is its surface. Every
332 //! consumer had written the danger rule itself. It joins the badge in taking
333 //! the four tones as colour, off `data-tone`.
334 //!
335 //! **A list rendered as a bulleted list**, because nothing here reset the `ul`
336 //! a renderer emits for one.
337 //!
338 //! `RowPart::revealed_on_hover` also stops being honoured, which its own doc
339 //! sanctioned: a renderer decides. It was retired outright in makeover-layout
340 //! 0.13.0, once this had been its only consumer for a release. The rule hid a
341 //! row's actions until hover,
342 //! and every escape it grew was a report that hiding was wrong for somebody:
343 //! `focus-within` for the keyboard, the capability gate for a fingertip with no
344 //! way to unhide. What survived hid the controls from pointer users alone, who
345 //! are the ones scanning a list to learn what can be done to a row.
346 //!
347 //! # 0.17.0: the depth classes stop being controls
348 //!
349 //! [`depth_rules`] gave `.raised` the whole interactive set. A depth is a
350 //! statement about shape, so that left the vocabulary with no raised surface
351 //! that is merely an object, and an app wanting one had two moves: write its
352 //! own class from tokens, or take a control class and cancel the control half.
353 //! goingson took the second, in three variants over sixteen elements
354 //! (`.card--static` at 14 call sites, `.card--muted` at 2, `.card--shell` at 1),
355 //! each re-asserting the resting fill and bevel on `:hover` and `:active`.
356 //!
357 //! Measured before changing it: `.raised` is emitted into goingson, Balanced
358 //! Breakfast and the MNW server, and none of the three has a single call site.
359 //! The states were unasked-for everywhere at once, and dropping them costs no
360 //! migration anywhere.
361 //!
362 //! `.card` and `.button` are unchanged. They are the same depth *and* controls,
363 //! and they take their states from [`surface_rules`], which is where a state
364 //! belongs: on the thing that claims to answer a pointer.
365 //!
366 //! # Substitution, three ways
367 //!
368 //! `Fill::Well` has no colour on makeover before 2.3.0, and each renderer
369 //! answers that differently, which is the evidence that dropping
370 //! `Fill::fallback` from the description was right:
371 //!
372 //! - `makeover-immediate` substitutes the page in Rust.
373 //! - `makeover-tui` refuses to substitute and draws an edge instead, because a
374 //! terminal would quantise the two together.
375 //! - here, CSS already has the mechanism: `var(--surface-well,
376 //! var(--surface-page))` falls back in the browser, and nothing in Rust
377 //! decides anything.
378
379 #![forbid(unsafe_code)]
380
381 pub mod facet;
382 pub mod figure;
383 pub mod form;
384 pub mod list;
385 pub mod meter;
386 pub mod placeholder;
387 pub mod vocabulary;
388
389 /// A render of every emitter, scraped for the classes it wrote.
390 ///
391 /// Test-only, and the guard behind [`vocabulary::names`]. See the module's own
392 /// header for why the check renders rather than reads the source.
393 #[cfg(test)]
394 mod corpus;
395
396 use crate::list::{cell_part_class, part_class};
397 use makeover_geometry::{Density, SizeClass};
398 // Re-exported rather than redefined. An app assembling its own stylesheet out
399 // of this crate's pieces needs the same layer name, and most such apps depend
400 // on this crate and not on `makeover-geometry` directly: goingson builds
401 // `tables.css` in its own build.rs from [`list::narrowing_css`], and those
402 // rules are as generated as the ones here.
403 pub use makeover_geometry::{CSS_LAYER, in_css_layer};
404
405 /// This crate's version, as the generated stylesheet reports it.
406 ///
407 /// A consumer whose lockfile still pins an old `makeover-webview` gets a
408 /// well-formed sheet with components missing and no error anywhere, so the
409 /// emitter has to name itself in what it writes. Read by
410 /// `makeover_build::layout_css` through [`stylesheet`].
411 pub const VERSION: &str = env!("CARGO_PKG_VERSION");
412 use makeover_layout::{
413 Bevel, CellPart, Depth, Fallback, Fill, Flow, Intent, RowPart, Selector, Sort, State, Token,
414 Tone,
415 };
416 use makeover_touch::Affordance;
417 use std::fmt::Write as _;
418
419 /// How the emitted CSS is shaped.
420 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
421 pub struct Emit {
422 /// Bevel thickness, as a CSS length.
423 ///
424 /// A value, so it arrives from the caller: border widths belong to
425 /// `makeover-geometry` and will come from there once it carries them.
426 pub border_width: &'static str,
427 /// Focus ring thickness, as a CSS length.
428 ///
429 /// Separate from [`border_width`](Self::border_width), which it reused
430 /// until 0.12.0. That reuse was an implementation convenience dressed as
431 /// consistency, and it emitted a 1px ring: a bevel and a focus indicator
432 /// are answering different questions, and only one of them has to be
433 /// noticed from across a desk.
434 ///
435 /// The default is the measured consensus rather than a new opinion. Every
436 /// consumer had already written its own ring and all three chose at least
437 /// 2px: the MNW server 2px across 10 rules, Balanced Breakfast 2px,
438 /// goingson 2px on three rules and 3px on the one covering twelve
439 /// selectors. The design system was the only thing in the tree saying 1px.
440 pub focus_width: &'static str,
441 /// Prefix for emitted class names, without the leading dot.
442 pub class_prefix: &'static str,
443 }
444
445 impl Default for Emit {
446 fn default() -> Self {
447 Self {
448 border_width: "1px",
449 focus_width: "2px",
450 class_prefix: "",
451 }
452 }
453 }
454
455 /// A string as CSS escapes, for a `content` value.
456 ///
457 /// `\u{25B2}` becomes `\25B2`. Emitted escaped rather than literally so the
458 /// stylesheet is ASCII whatever the description spells: a `content` string is
459 /// read by whatever encoding the consumer serves the file as, and a caret that
460 /// depends on that is a caret that works on one machine.
461 ///
462 /// Terminated by the closing quote at every site here. A CSS hex escape takes
463 /// up to six digits and ends at the first character that cannot be one, so an
464 /// escape followed by more text would need a space that these do not.
465 fn css_escape(text: &str) -> String {
466 text.chars().fold(String::new(), |mut out, c| {
467 let _ = write!(out, "\\{:X}", c as u32);
468 out
469 })
470 }
471
472 /// The CSS custom property holding a bevel's composition.
473 #[must_use]
474 pub fn bevel_var(bevel: Bevel) -> &'static str {
475 match bevel {
476 Bevel::Raised => "--bevel-raised",
477 Bevel::Inset => "--bevel-inset",
478 }
479 }
480
481 /// A `var()` reference to a fill intent, with the browser's own fallback where
482 /// the intent may be absent.
483 ///
484 /// The fallback is CSS syntax, not a decision made here. That is the whole
485 /// difference between this renderer and the other two.
486 #[must_use]
487 pub fn fill_var(fill: Fill) -> String {
488 match fill {
489 Fill::Well => format!("var(--{}, var(--{}))", fill.token(), Fill::Page.token()),
490 other => format!("var(--{})", other.token()),
491 }
492 }
493
494 /// The two-tone edge as a `box-shadow` value.
495 ///
496 /// Two inset shadows, one per corner pair: the light one offset down and
497 /// right so it lands on the top and left edges, the dark one the other way.
498 /// The same assignment `makeover-immediate` draws with polylines and
499 /// `makeover-tui` draws with box-drawing characters.
500 #[must_use]
501 pub fn bevel_shadow(bevel: Bevel, opts: &Emit) -> String {
502 let (top_left, bottom_right) = bevel.edges();
503 let w = opts.border_width;
504 format!(
505 "inset {w} {w} 0 var(--{}), inset -{w} -{w} 0 var(--{})",
506 top_left.token(),
507 bottom_right.token()
508 )
509 }
510
511 /// The custom properties both bevels resolve through.
512 ///
513 /// Emitted as properties rather than inlined into every rule because that is
514 /// what the apps already do, and because a consumer that wants the edge
515 /// without the fill reads the property directly.
516 #[must_use]
517 pub fn bevel_properties(opts: &Emit) -> String {
518 let mut css = String::new();
519 for bevel in [Bevel::Raised, Bevel::Inset] {
520 let _ = writeln!(
521 css,
522 " {}: {};",
523 bevel_var(bevel),
524 bevel_shadow(bevel, opts)
525 );
526 }
527 css.push_str(ELEVATION_PROPERTY);
528 css
529 }
530
531 /// The cast shadow of a surface that floats over the page.
532 ///
533 /// Composed here for the reason the bevel pair is: `makeover` derives the tone,
534 /// this crate owns the geometry, and neither has to know the other's numbers.
535 ///
536 /// **Only for a surface that overlays the page.** A menu, a toast, a popover, a
537 /// dropdown. A surface *in* the page takes `.raised` and its bevel, and a rule
538 /// that reaches for this on a card or a plate has renamed a literal rather than
539 /// replaced it.
540 ///
541 /// Two lengths rather than one, because a single blur reads as a smudge at
542 /// plate size and as a halo at menu size. The offset is small and downward: a
543 /// Platinum-era menu sits just off the page rather than hovering above it.
544 const ELEVATION_PROPERTY: &str =
545 " --elevation-overlay: 0 2px 4px var(--elevation), 0 8px 24px var(--elevation);\n";
546
547 /// The class name for a depth.
548 #[must_use]
549 pub fn depth_class(depth: Depth, opts: &Emit) -> Option<String> {
550 let name = match depth {
551 Depth::Flat => return None,
552 Depth::Raised => "raised",
553 Depth::Well => "well",
554 Depth::Sunken => "sunken",
555 // A depth added to the description since this renderer was last
556 // built. No class, on the same footing as Flat: emitting a name
557 // whose rule body we cannot write would put a class in the markup
558 // that the stylesheet never defines.
559 _ => return None,
560 };
561 Some(format!("{}{name}", opts.class_prefix))
562 }
563
564 /// A prefixed class name.
565 ///
566 /// Public since 0.27.0, for the renderers that emit markup this crate does not.
567 /// A screen renderer writing `class="row"` has to prefix it the way the
568 /// stylesheet half does or a prefixed app gets rules matching everything except
569 /// the elements that renderer wrote, and the failure is invisible: the CSS
570 /// stays valid and one element is unstyled. quasi-webview carried a byte
571 /// identical copy of this function until it could call this one.
572 #[must_use]
573 pub fn class(name: &str, opts: &Emit) -> String {
574 let mut out = String::with_capacity(opts.class_prefix.len() + name.len());
575 push_class(&mut out, name, opts);
576 out
577 }
578
579 /// A prefixed class name, written into a buffer the caller already has.
580 ///
581 /// The form the emitters use, and the reason it exists is [`escape_into`]'s:
582 /// every class on every element went through a `format!` before 0.40.0,
583 /// including the default case where the prefix is empty and the answer is the
584 /// argument. A described table row carried roughly eighty transient
585 /// allocations, and this and the escaper were most of them.
586 ///
587 /// [`class`] stays for callers holding a name rather than a buffer.
588 ///
589 /// [`escape_into`]: crate::form::escape_into
590 pub fn push_class(out: &mut String, name: &str, opts: &Emit) {
591 out.push_str(opts.class_prefix);
592 out.push_str(name);
593 }
594
595 /// The class an option of a selector carries, which is what the rules key off.
596 ///
597 /// Named for the option and not for the group: [`selector_rules`] styles the
598 /// thing that gets picked, so `Selector::Tabs` is `tab` and not `tabs`. The
599 /// distinction is not pedantry. quasi-webview spelled these `tabs`, `segmented`
600 /// and `option`, put `toggle` on the wrapping element rather than on the
601 /// buttons inside it, and every described selector in that renderer came out
602 /// with no depth, no focus ring and no chosen state, while the toggle group got
603 /// a bevel meant for its buttons.
604 ///
605 /// The chosen option additionally carries `chosen`, the same way a latched chip
606 /// carries `latched`. That name is this crate's too; there is no reason for a
607 /// caller to spell it, and [`selector_rules`] is where it is written down.
608 #[must_use]
609 pub fn option_class(selector: Selector) -> &'static str {
610 match selector {
611 Selector::Tabs => "tab",
612 Selector::Segmented => "segment",
613 Selector::Toggle => "toggle",
614 }
615 }
616
617 /// The fill and edge declarations for a depth, as a rule body.
618 ///
619 /// Empty for [`Depth::Flat`], which has neither and inherits what it sits on.
620 /// Callers lean on the emptiness to skip the rule rather than emit a class that
621 /// sets nothing: a class that sets no properties is a class that means "I
622 /// thought about this", which is what comments are for.
623 ///
624 /// The two halves are emitted independently because [`Depth::Sunken`] has a
625 /// fill and no bevel. Requiring both, which this did before makeover-layout
626 /// 0.3.0, silently dropped the fill for exactly that case. Independent does not
627 /// mean unpaired: both halves still come off one `Depth`, so they cannot
628 /// disagree about what the region is.
629 #[must_use]
630 pub fn depth_declarations(depth: Depth) -> String {
631 let mut css = String::new();
632 if let Some(fill) = depth.fill() {
633 let _ = writeln!(css, " background: {};", fill_var(fill));
634 }
635 if let Some(bevel) = depth.bevel() {
636 let _ = writeln!(css, " box-shadow: var({});", bevel_var(bevel));
637 }
638 css
639 }
640
641 /// One rule giving a selector a depth, or nothing when the depth declares
642 /// nothing.
643 #[must_use]
644 pub fn depth_rule(selector: &str, depth: Depth) -> String {
645 let body = depth_declarations(depth);
646 if body.is_empty() {
647 return String::new();
648 }
649 format!(".{selector} {{\n{body}}}\n")
650 }
651
652 /// The media condition a hover rule has to sit inside, or `None` if hover is
653 /// unconditional.
654 ///
655 /// Two crates answer this and neither answer is made here. `makeover-touch`
656 /// owns *whether* hover exists at a density, and `makeover-geometry` owns how
657 /// that capability is spelled as a media condition. Asking both is what stops
658 /// this renderer minting a third opinion, which is what all three apps did:
659 /// goingson sniffed the user agent, Balanced Breakfast used `(hover: none)`
660 /// alone, and the MNW server had no gate at all.
661 ///
662 /// [`SizeClass`] is required by [`Affordance::available`] and ignored by this
663 /// member, which reports as much through `reads_size`. Passing Compact is not
664 /// a claim about width; the test below pins that every class agrees.
665 fn hover_condition() -> Option<&'static str> {
666 if Affordance::Hover.available(Density::Touch, SizeClass::Compact) {
667 // A fingertip grew a hover state. Nothing to gate, and this renderer
668 // should not invent a reason to gate anyway.
669 None
670 } else {
671 Some(Density::Pointer.media_condition())
672 }
673 }
674
675 /// Put a rule inside a media query, or leave it alone.
676 fn gated(condition: Option<&str>, rule: &str) -> String {
677 let Some(condition) = condition else {
678 return rule.to_string();
679 };
680 let mut css = format!("@media {condition} {{\n");
681 for line in rule.lines() {
682 // Blank lines stay blank. Indenting one leaves trailing whitespace,
683 // which is the sort of thing a formatter later reverts and calls a diff.
684 if line.is_empty() {
685 css.push('\n');
686 } else {
687 let _ = writeln!(css, " {line}");
688 }
689 }
690 css.push_str("}\n");
691 css
692 }
693
694 /// The keyboard focus ring, placed by the depth it lands on.
695 ///
696 /// This is the webview's **focus ring** and nothing more. **Reach** and
697 /// **focus** are both the browser's — the document decides what is reachable
698 /// and `:focus-visible` decides which reached thing wears the ring — and no
699 /// description states either. The three terms are defined once in
700 /// `makeover_layout`'s crate header, "Reach, focus and the focus ring".
701 ///
702 /// One ring for the whole system, because a focus ring's job is to be
703 /// recognised and three apps having three of them is the failure. What varies
704 /// is where it sits, and that comes off [`Depth`] rather than off a per-
705 /// component choice: a well takes the ring inside its own edge, and anything
706 /// standing proud of the page takes it outside.
707 ///
708 /// `outline` rather than the composed `box-shadow` the invalid-field ring at
709 /// [`field_rules`] uses, and deliberately the one place the two rings are built
710 /// differently. A `box-shadow` ring has to restate the bevel beside it, because
711 /// `box-shadow` is not additive and a lone ring silently drops the well out
712 /// from under the element. That restatement is a second copy of the depth,
713 /// living in a different function from the first, and it is exactly the
714 /// duplication `Depth` exists to prevent. `outline` occupies its own property,
715 /// so the bevel survives untouched and there is nothing to keep in agreement.
716 /// They render the same: both are a flush ring one border-width wide.
717 #[must_use]
718 pub fn focus_rule(selector: &str, depth: Depth, opts: &Emit) -> String {
719 let w = opts.focus_width;
720 // Same magnitude either way, and only the sign comes off the depth. Both
721 // values are what the consumers had already converged on independently:
722 // 2px out is what all three wrote, and 2px in is the MNW server's own
723 // answer for the one inset ring it had.
724 let offset = match depth.bevel() {
725 // Inside the well, clear of its edge rather than painted over it.
726 Some(Bevel::Inset) => format!("calc(-1 * {w})"),
727 // Raised, or no edge at all. Outside, standing off by its own width.
728 _ => w.to_string(),
729 };
730 // The token by name. It is `makeover`'s, derived from the action colour,
731 // and reaching it through a description member was a second path to the
732 // same variable for as long as one existed.
733 format!(
734 ".{selector}:focus-visible {{\n outline: {w} solid var(--focus-ring);\n outline-offset: {offset};\n}}\n"
735 )
736 }
737
738 /// Present, visible, and not answering.
739 ///
740 /// Matches the ARIA attribute as well as the pseudo-class, because `:disabled`
741 /// only matches form elements and half the things this crate emits are not
742 /// one: a `div` carrying `.chip` or `.tab` can never be `:disabled`. Keying on
743 /// the accessible state is the pattern [`field_rules`] already establishes for
744 /// `aria-invalid`, on the reasoning that one fact read by both the styling and
745 /// the accessibility tree cannot drift from itself.
746 ///
747 /// The rest depth is re-asserted rather than assumed, because this rule has to
748 /// beat the hover and pressed rules above it. It does that on source order at
749 /// equal specificity, not by out-specifying them: every rule this function's
750 /// caller emits is (0,2,0), and adding a `:not(:disabled)` anywhere would raise
751 /// one of them and have to be unpicked when this output moves inside its own
752 /// cascade layer.
753 #[must_use]
754 pub fn disabled_rule(selector: &str, depth: Depth) -> String {
755 format!(
756 ".{selector}:disabled,\n.{selector}[aria-disabled=\"true\"] {{\n{} color: var(--{});\n cursor: not-allowed;\n}}\n",
757 depth_declarations(depth),
758 State::Disabled.token()
759 )
760 }
761
762 /// Every state a selector that answers a click implies: hover, pressed, focus
763 /// and disabled, in that order.
764 ///
765 /// Order is the whole cascade mechanism here. All four selectors are
766 /// specificity (0,2,0), so disabled wins over hover and pressed by coming last
767 /// and by nothing else.
768 ///
769 /// Pressed emits [`Depth::pressed`] in full, fill and edge together. Emitting
770 /// only the edge is what left goingson hand-writing `background:
771 /// var(--surface-sunken)` on three separate rules, and a fill that does not
772 /// travel with its edge is precisely the disagreement `Depth` exists to make
773 /// unrepresentable. So the pressed fill comes from the description
774 /// (`--surface-well`) rather than from whatever each app reached for.
775 ///
776 /// Hover has no member in the description and is renderer policy: a terminal
777 /// and an immediate-mode painter have no hover to express. It resolves against
778 /// `--hover-surface`, which `makeover` already derives and which nothing
779 /// consumed until now. What it *is* gated on is capability, via
780 /// [`hover_condition`]. Before that gate existed the apps each wrote their own:
781 /// goingson's section 60 exists solely to take back the hover state this
782 /// function had just handed it, by out-specifying a rule it does not own.
783 ///
784 /// `depth` is the selector's **rest** depth, used to place the focus ring and
785 /// to restore the surface under a disabled control. The pressed rule keeps
786 /// inverting from [`Depth::Raised`] regardless, which is what every caller got
787 /// before this parameter existed: a tab's unchosen depth is
788 /// [`Depth::Sunken`], and `Sunken.pressed()` is `Sunken`, so deriving the press
789 /// from the rest depth would leave a tab with no press at all.
790 #[must_use]
791 pub fn interactive_rules(selector: &str, depth: Depth, opts: &Emit) -> String {
792 let mut css = gated(
793 hover_condition(),
794 &format!(".{selector}:hover {{\n background: var(--hover-surface);\n}}\n"),
795 );
796 css.push_str(&depth_rule(
797 &format!("{selector}:active"),
798 Depth::Raised.pressed(),
799 ));
800 css.push_str(&focus_rule(selector, depth, opts));
801 css.push_str(&disabled_rule(selector, depth));
802 css
803 }
804
805 /// One rule per depth: its fill and its edge, together.
806 ///
807 /// A depth and nothing else. `.raised` says a surface sits on what is behind
808 /// it, which is a statement about the shape and not about what happens when a
809 /// pointer arrives, so it emits no hover, press, focus or disabled rule. The
810 /// named surfaces are where interaction lives: `.card` and `.button` are the
811 /// same depth *and* controls, and they get their states from
812 /// [`surface_rules`].
813 ///
814 /// This class carried the interactive set until 0.17.0, which left the
815 /// vocabulary with no raised surface that is merely an object. Consumers that
816 /// needed one took a control class and cancelled half of it instead: sixteen
817 /// elements in goingson across three `.card--*` variants, each re-asserting the
818 /// resting fill and bevel on `:hover` and `:active`. Nothing anywhere used
819 /// `.raised` itself, so the states were unasked-for in every consumer at once.
820 #[must_use]
821 pub fn depth_rules(opts: &Emit) -> String {
822 let mut css = String::new();
823 for depth in [Depth::Raised, Depth::Well] {
824 let Some(class) = depth_class(depth, opts) else {
825 continue;
826 };
827 css.push_str(&depth_rule(&class, depth));
828 }
829 css
830 }
831
832 /// The three surfaces that are a depth with a name.
833 ///
834 /// `button` and `card` are both [`Depth::Raised`], and `field` is a
835 /// [`Depth::Well`] because that is the reading `Depth`'s own documentation
836 /// gives a text field. Their bodies come out identical by construction rather
837 /// than by hand: three hand-written copies in goingson's stylesheet is what
838 /// phase A deletes, and generating them from one call is what stops them
839 /// drifting apart again.
840 fn surface_rules(opts: &Emit) -> String {
841 let mut css = String::new();
842 for name in ["button", "card"] {
843 let c = class(name, opts);
844 css.push_str(&depth_rule(&c, Depth::Raised));
845 css.push_str(&interactive_rules(&c, Depth::Raised, opts));
846 }
847
848 let field = class("field", opts);
849 css.push_str(&depth_rule(&field, Depth::Well));
850
851 // A field takes focus and refuses input like everything else here, and got
852 // neither until now, which is why all three apps hand-write a focus ring
853 // for it and no two of them match. No hover or pressed: a text field does
854 // not light up under the pointer and does not invert when clicked, so the
855 // two states `interactive_rules` would add are the two it does not have.
856 css.push_str(&focus_rule(&field, Depth::Well, opts));
857 css.push_str(&disabled_rule(&field, Depth::Well));
858
859 // Keyed on the ARIA attribute rather than on a class, so the visual state
860 // and the accessible state cannot drift apart: there is one fact and both
861 // read it. goingson already drove its invalid styling this way and was
862 // right to; the `.invalid` class this emitted before 0.5.0 was a second
863 // place to forget.
864 //
865 // The ring composes *after* the bevel rather than replacing it. box-shadow
866 // is not additive, so a lone ring silently dropped the well out from under
867 // an invalid field. Flat and unlit: this edge is saying "wrong", and
868 // lighting one side would have it say "raised" at the same time.
869 let _ = writeln!(
870 css,
871 ".{field}[aria-invalid=\"true\"] {{\n box-shadow: var({}), 0 0 0 {} var(--danger);\n}}",
872 bevel_var(Bevel::Inset),
873 opts.border_width
874 );
875 css
876 }
877
878 /// Badges and chips.
879 ///
880 /// The one place phase A changes how goingson looks rather than only where its
881 /// rules live. [`Token::Badge`] is [`Depth::Flat`], so a badge emits no fill
882 /// and no edge at all, where goingson ships `.tag, .badge` as a single rule
883 /// carrying the raised bevel. Splitting that means reading every call site to
884 /// decide which of the two it always was.
885 ///
886 /// What a badge does carry is a [`Tone`], the intent family it shares with
887 /// notices and nothing else. Neutral is the bare class rather than a variant,
888 /// because it is the absence of a status and not a status called "none".
889 /// Text that goes somewhere.
890 ///
891 /// The one inline control, and the vocabulary had no word for it until a
892 /// description layer needed one. A table cell has carried `cell-link` since
893 /// 0.14.0's part list, deliberately unruled because the cell's own rule covers
894 /// it; what was missing is the same thing outside a table, which is what a
895 /// described run holds when a sentence contains a link.
896 ///
897 /// Colour and underline only. Whether a link is inline in a sentence or sitting
898 /// on its own line is the app's layout, and how much room it takes is
899 /// `makeover-geometry`'s. What is here is the pair of signals that say "this
900 /// goes somewhere" and nothing that says where it sits.
901 ///
902 /// The visited arm is deliberately absent. A link inside an app points at the
903 /// app's own screens, which the user is expected to have been to, so painting
904 /// them differently marks almost everything and distinguishes nothing.
905 fn link_rules(opts: &Emit) -> String {
906 let mut css = String::new();
907 let link = class("link", opts);
908
909 let _ = writeln!(
910 css,
911 ".{link} {{\n color: var(--action);\n \
912 text-decoration: underline;\n}}"
913 );
914 // The hover step is the same one every other control takes, and it is a
915 // colour rather than a surface: a link has no box to raise.
916 let _ = writeln!(
917 css,
918 "@media (hover: hover) and (pointer: fine) {{\n .{link}:hover \
919 {{\n color: var(--action-hover);\n }}\n}}"
920 );
921 let _ = writeln!(
922 css,
923 ".{link}:focus-visible {{\n outline: {} solid var(--focus-ring);\n \
924 outline-offset: 2px;\n}}",
925 opts.focus_width
926 );
927 // A link is often a `<button>` rather than an `<a>`: a renderer picks the
928 // element from the method, so a link that writes is a button that has to
929 // stop looking like one.
930 let _ = writeln!(
931 css,
932 "button.{link} {{\n background: none;\n border: none;\n \
933 padding: 0;\n font: inherit;\n cursor: pointer;\n}}"
934 );
935 css
936 }
937
938 fn token_rules(opts: &Emit) -> String {
939 let mut css = String::new();
940
941 // No `depth_rule` call here, deliberately: `Token::Badge.depth(_)` is Flat,
942 // and a label with an edge says it can be pressed.
943 let badge = class("badge", opts);
944 let _ = writeln!(
945 css,
946 ".{badge} {{\n color: var(--{});\n}}",
947 Tone::Neutral.token()
948 );
949 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
950 let _ = writeln!(
951 css,
952 ".{badge}[data-tone=\"{0}\"] {{\n color: var(--{0});\n}}",
953 tone.token()
954 );
955 }
956
957 // A button carries the four tones a badge does. It had none, on the reading
958 // that a control's colour is its surface rather than its text, and that
959 // reading has one hole big enough to matter: the button that destroys
960 // something. Every consumer had written that rule itself, and a description
961 // that says `Tone::Danger` on an act had nowhere for it to land.
962 //
963 // Colour and not a fill, matching the badge. A red surface is a decision
964 // about emphasis that belongs to an app's own layer, and two of them
965 // fighting is worse than neither.
966 let button = class("button", opts);
967 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
968 let _ = writeln!(
969 css,
970 ".{button}[data-tone=\"{0}\"] {{\n color: var(--{0});\n}}",
971 tone.token()
972 );
973 }
974
975 // A chip holds itself down, which is `Depth::pressed` arrived at
976 // independently by two apps. `removable` is a remove affordance, so it is
977 // markup and waits for phase B.
978 let chip = class("chip", opts);
979 let unlatched = Token::Chip { removable: false };
980 css.push_str(&depth_rule(&chip, unlatched.depth(false)));
981 css.push_str(&interactive_rules(&chip, unlatched.depth(false), opts));
982 css.push_str(&depth_rule(
983 &format!("{chip}.latched"),
984 unlatched.depth(true),
985 ));
986 css
987 }
988
989 /// The three selectors, each named by what it picks.
990 ///
991 /// A tab comes *forward* to join the pane it opens, which is why
992 /// [`Selector::Tabs`] chooses [`Depth::Raised`] where a segment and a toggle
993 /// are held in. That is the folder semantic, and it is the whole reason the
994 /// three are not one member with a flag.
995 ///
996 /// [`Selector::abutting`] is not emitted: whether the options touch is
997 /// spacing, and spacing is `makeover-geometry`'s question to answer.
998 ///
999 /// Both states emit as of makeover-layout 0.3.0. Before it the description
1000 /// named only the chosen option, so an unchosen one fell through to
1001 /// [`Depth::Flat`] and nothing was drawn for it, which left goingson's tab
1002 /// strip hand-writing the recess that makes its chosen tab read as forward.
1003 fn selector_rules(opts: &Emit) -> String {
1004 let mut css = String::new();
1005 for selector in [Selector::Tabs, Selector::Segmented, Selector::Toggle] {
1006 let c = class(option_class(selector), opts);
1007 css.push_str(&depth_rule(&c, selector.unchosen()));
1008 css.push_str(&interactive_rules(&c, selector.unchosen(), opts));
1009 css.push_str(&depth_rule(&format!("{c}.chosen"), selector.chosen()));
1010 }
1011 css
1012 }
1013
1014 /// The parts of a list row.
1015 ///
1016 /// The list is written out rather than derived because `RowPart` is
1017 /// `#[non_exhaustive]` as of makeover-layout 0.9.0, so there is nothing to
1018 /// iterate. A member added upstream emits no rule until it is named here, which
1019 /// is the trade `non_exhaustive` makes: a silent gap instead of a build break.
1020 /// [`part_class`] carries the same list and the same obligation.
1021 fn row_rules(opts: &Emit) -> String {
1022 let mut css = String::new();
1023
1024 // The container the rows sit in. Three zeroes and a keyword, all of them
1025 // undoing a browser default the description never asked for: a described
1026 // list of SSH keys is not a bulleted list, and it rendered as one because
1027 // nothing here said otherwise. Not a size: there is no magnitude in it,
1028 // which is the line this crate holds.
1029 let _ = writeln!(
1030 css,
1031 ".{} {{\n list-style: none;\n margin: 0;\n padding: 0;\n}}",
1032 class("list", opts)
1033 );
1034
1035 for part in [
1036 RowPart::Primary,
1037 RowPart::Secondary,
1038 RowPart::Meta,
1039 RowPart::Actions,
1040 RowPart::Tokens,
1041 RowPart::Proportion,
1042 ] {
1043 let c = class(part_class(part), opts);
1044
1045 // Actions carry controls rather than text, and `RowPart::intent` says
1046 // so by returning the same intent inheriting already gives. Pinning it
1047 // would be louder than saying nothing. Tokens answer alike, for their
1048 // own reason: each token carries its own tone, and a colour on the
1049 // strip would fight the things sitting in it. A proportion is the same
1050 // case again: the meter inside carries the tone.
1051 if !matches!(
1052 part,
1053 RowPart::Actions | RowPart::Tokens | RowPart::Proportion
1054 ) {
1055 let _ = writeln!(css, ".{c} {{\n color: var(--{});\n}}", part.intent());
1056 }
1057
1058 // A row's actions are shown at rest. `RowPart::revealed_on_hover` said
1059 // otherwise and was not honoured here from 0.23.0; makeover-layout
1060 // 0.13.0 retired the method, so there is no longer a description saying
1061 // one thing and a renderer doing another.
1062 //
1063 // The rule was `opacity: 0` gated to pointer devices, revealed on
1064 // `:hover` and on `:focus-within`. Each escape it needed was a report
1065 // that hiding was wrong for somebody: `focus-within` because tabbing
1066 // could never reach an action; the gate because a fingertip had no way
1067 // to unhide, which both webview apps had already hand-written
1068 // `opacity: 1` to undo. What was left was a control hidden from
1069 // exactly one group: people using a pointer, who are also the group
1070 // scanning a list to find out what can be done to a row.
1071 //
1072 // A settings screen is where that reads worst: the whole reason to be
1073 // on it is to remove a key, and the button doing so was invisible
1074 // until pointed at. A table cell's actions were never hidden, so the
1075 // two arrangements now agree.
1076 }
1077
1078 // A part that may take two lines. `Flow::Tight` gets no rule: one line is
1079 // what a run already does, and restating it here would put a declaration on
1080 // every part in every row to say nothing.
1081 //
1082 // This is the shape both webview apps had already written by hand and
1083 // commented -- Balanced Breakfast on a feed row's title, goingson on a
1084 // problem's body -- which is the whole argument for the description
1085 // carrying it. `-webkit-` prefixed and unprefixed together: the prefixed
1086 // trio is what every engine actually implements, and `line-clamp` is the
1087 // standard property landing behind it.
1088 let _ = writeln!(
1089 css,
1090 ".{} {{\n display: -webkit-box;\n -webkit-box-orient: vertical;\n -webkit-line-clamp: {lines};\n line-clamp: {lines};\n overflow: hidden;\n}}",
1091 class("row-relaxed", opts),
1092 lines = Flow::Relaxed.lines()
1093 );
1094
1095 css
1096 }
1097
1098 /// A row of things that share their space, and what each fallback gets here.
1099 ///
1100 /// Ruling: wiki `layout-room-and-fallback`, Max 2026-08-18. The bug it answers
1101 /// is goingson's `styles.css:702`, which pinned every `.page-header` over the
1102 /// pill strip with `position: absolute` and so took the toolbar out of flow:
1103 /// zero width contributed to the row it shared, nothing able to collide with
1104 /// it, and therefore nothing preventing the collision. Rule 1 of the ruling is
1105 /// that every described member is in flow, and these rules are how that is kept
1106 /// rather than asked for.
1107 ///
1108 /// # The floor, which is most of the fix
1109 ///
1110 /// `.run > *` gets `min-width: min-content`. That is the derived minimum the
1111 /// ruling asks for, in this renderer's own unit and stated by the browser
1112 /// rather than by anybody: a member cannot be squeezed narrower than what is
1113 /// in it, so members in one flow push each other instead of overlapping. It
1114 /// costs no query and no number, and it is what fixes all four measured widths
1115 /// whichever fallback the group declared.
1116 ///
1117 /// # What each fallback gets, exactly
1118 ///
1119 /// [`Fallback::Wrap`] is `flex-wrap: wrap`, which is exact. The browser wraps
1120 /// the run when the members no longer fit, deciding that from their own
1121 /// intrinsic widths, which is the derived minimum doing the whole job.
1122 ///
1123 /// [`Fallback::Stack`] is wrap plus `flex: 1 1 max-content` on the members, so
1124 /// a member that cannot sit beside its sibling takes a line of its own and
1125 /// fills it. For the two-member run this was ruled on -- a tab strip and a
1126 /// band -- that is precisely "a row becomes a column".
1127 ///
1128 /// [`Fallback::Shed`] and [`Fallback::Menu`] get wrap, and this renderer is
1129 /// honouring less than the description says. **CSS cannot express either one
1130 /// without breaking the ruling's own first constraint.** Both need to know that
1131 /// the run is out of room in order to take a member out of it, a container
1132 /// query is the only construct that can ask, and `@container` compares against
1133 /// a `<length>` -- there is no `@container (inline-size < min-content)`. So
1134 /// every honest spelling of Shed here needs an authored breakpoint, which is
1135 /// the thing the ruling exists to forbid, and the dishonest ones are worse: a
1136 /// clamped height clips by document order rather than by [`Priority`], and
1137 /// `display: none` under a viewport `@media` is the `nth-child(n+5)` bug the
1138 /// vocabulary replaced.
1139 ///
1140 /// Wrapping is the right thing to do instead. It keeps every member reachable,
1141 /// which is the property that was actually broken -- goingson's new-contact
1142 /// button left the viewport entirely at 560 -- and it keeps rule 1. A renderer
1143 /// answering with less than was described is precedented and deliberate here:
1144 /// [`makeover_layout::Region::Columns`] says a terminal stacking a board's
1145 /// columns is honouring the description rather than degrading it.
1146 ///
1147 /// The real mechanism needs the shed members to have somewhere to go, which is
1148 /// markup and belongs to quasi-webview: an overflow control is a member of the
1149 /// run, and the description does not yet say that a member *is* one. Filed
1150 /// rather than guessed at.
1151 fn run_rules(opts: &Emit) -> String {
1152 let run = class("run", opts);
1153 let mut css = String::new();
1154
1155 // `flex-wrap: nowrap` is stated rather than left to the default, because
1156 // the fallbacks below are read as overrides of this line and a reader
1157 // should not have to know which way flexbox leans to see that.
1158 //
1159 // No gap. Spacing between members is the app's, the same way this crate
1160 // states no margins anywhere else; a gap here would be a size, and the one
1161 // hardcoded size in the mechanism is makeover-geometry's contact patch.
1162 let _ = writeln!(
1163 css,
1164 ".{run} {{\n display: flex;\n flex-wrap: nowrap;\n align-items: center;\n}}"
1165 );
1166
1167 // The derived minimum, and the whole reason a member can no longer be
1168 // overlapped. `min-width: auto` is flexbox's default for a flex item and is
1169 // *not* the same thing: auto lets an item be compressed below its content
1170 // in a nowrap run, which is how a toolbar ends up drawn over a tab strip
1171 // even without anything leaving the flow.
1172 let _ = writeln!(css, ".{run} > * {{\n min-width: min-content;\n}}");
1173
1174 for fallback in [
1175 Fallback::Wrap,
1176 Fallback::Stack,
1177 Fallback::Shed,
1178 Fallback::Menu,
1179 ] {
1180 let name = fallback_class(fallback);
1181 let c = class(name, opts);
1182 let _ = writeln!(css, ".{c} {{\n flex-wrap: wrap;\n}}");
1183 if matches!(fallback, Fallback::Stack) {
1184 let _ = writeln!(css, ".{c} > * {{\n flex: 1 1 max-content;\n}}");
1185 }
1186 }
1187
1188 css
1189 }
1190
1191 /// Every class [`fallback_class`] can return, plus the run itself.
1192 ///
1193 /// [`ROW_PART_CLASSES`](crate::list::ROW_PART_CLASSES)'s reasoning and the same
1194 /// obligation: a `match` over a `#[non_exhaustive]` enum cannot be enumerated
1195 /// from outside, so the list sits beside it and a test holds the two together.
1196 /// `run` is in it because it is emitted in its own right rather than only as a
1197 /// fallback's fallback.
1198 pub const RUN_CLASSES: &[&str] = &["run", "run-wrap", "run-stack", "run-shed", "run-menu"];
1199
1200 /// The class a run carries for what it does when it is tight.
1201 ///
1202 /// A run always carries `.run` as well, so an unrecognised fallback -- the enum
1203 /// is `#[non_exhaustive]` -- lands as a plain nowrap row with the min-content
1204 /// floor still under it. That is the safe failure: every member in flow and
1205 /// none overlapped, which is the property, with only the rearrangement missing.
1206 #[must_use]
1207 pub fn fallback_class(fallback: Fallback) -> &'static str {
1208 match fallback {
1209 Fallback::Wrap => "run-wrap",
1210 Fallback::Stack => "run-stack",
1211 Fallback::Shed => "run-shed",
1212 Fallback::Menu => "run-menu",
1213 _ => "run",
1214 }
1215 }
1216
1217 /// The progress trough these rules fill.
1218 ///
1219 /// This was renderer-local chrome with nothing behind it until makeover-layout
1220 /// 0.10.0, which is the unusual order: the tones below were emitted for every
1221 /// bar in the tree while the only way to describe one was to concatenate the
1222 /// numbers into a heading. `Meter` is the word that arrived late, and
1223 /// [`meter::meter_html`](crate::meter::meter_html) is what now fills these.
1224 ///
1225 /// The rules stay a superset of what a description can ask for. An app drawing
1226 /// its own bar keeps these classes, which is what the four goingson grew
1227 /// independently were adopted onto.
1228 ///
1229 /// The trough is a [`Depth::Well`], the same reading a text field gets:
1230 /// something with its content down inside it.
1231 fn progress_rules(opts: &Emit) -> String {
1232 let progress = class("progress", opts);
1233 // `progress-fill` rather than a bare `fill`: an unprefixed build claims
1234 // these names in the app's own stylesheet, and `.fill` is grabby enough to
1235 // catch things that have nothing to do with progress. goingson already
1236 // calls it `.progress-fill`, so this is also the name that deletes.
1237 let fill = class("progress-fill", opts);
1238 let mut css = depth_rule(&progress, Depth::Well);
1239
1240 // The untoned bar is `--action`, not [`Tone::Neutral`]. That is the one
1241 // place this differs from the badge rules, and deliberately: a badge with
1242 // no status is a muted label, while a bar with no status is still
1243 // reporting progress, and `content-muted` would read as disabled.
1244 let _ = writeln!(
1245 css,
1246 ".{progress} > .{fill} {{\n background: var(--action);\n}}"
1247 );
1248
1249 // A bar can be saying something, same as a badge: goingson colours subtask
1250 // progress as success and an over-estimate as danger, which is real
1251 // information rather than decoration. Emitting the tones is what lets that
1252 // survive adoption instead of staying hand-written.
1253 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
1254 let _ = writeln!(
1255 css,
1256 ".{progress} > .{fill}[data-tone=\"{0}\"] {{\n background: var(--{0});\n}}",
1257 tone.token()
1258 );
1259 }
1260 css
1261 }
1262
1263 /// What a wait looks like, for the attribute that has been describing one to
1264 /// nobody.
1265 ///
1266 /// Wiki `loading-and-progress-standard`, phase 2. `data-awaiting` has been
1267 /// emitted since the vocabulary gained `Awaiting`, with
1268 /// `data-awaiting="determinate"` and a `data-awaiting-amount` beside it or
1269 /// `data-awaiting="indeterminate"` alone, and until 0.60.0 **nothing in the tree
1270 /// styled either**. Determinate and indeterminate rendered identically, which is
1271 /// to say not at all. This is the half that was missing.
1272 ///
1273 /// # Why it is keyed on `aria-busy` and not on the attribute alone
1274 ///
1275 /// `data-awaiting` is a fact about the control: pressing this waits. It is true
1276 /// when the page is painted and it stays true. Whether a wait is *running* is
1277 /// true only between two events, so it is the binder's to set, and `aria-busy`
1278 /// is the standard spelling of it — announced as well as drawn, which a class
1279 /// of our own would not be.
1280 ///
1281 /// That also keeps this crate out of any one client library's vocabulary.
1282 /// `quasi-webview` sets `aria-busy` from htmx's request events; a host driving
1283 /// the same markup another way sets it the same way and gets the same drawing.
1284 ///
1285 /// # The two drawings
1286 ///
1287 /// One pseudo-element either way, so no renderer has to emit an extra node.
1288 ///
1289 /// Indeterminate is the activity mark of rule 2: a small square that blinks.
1290 /// Determinate is a trough with a fill, drawn as a single gradient whose stop is
1291 /// `--awaiting-share`, a plain number from 0 to 1 that the binder sets from
1292 /// bytes it has actually watched land. A determinate control with nothing
1293 /// setting the share draws an empty trough rather than a full one, which is the
1294 /// honest reading: the size is known and the delivery is not.
1295 ///
1296 /// **What the bar may not do**, from rule 1 and from `Awaiting`'s own docs:
1297 /// what is done over what there is, and never a remaining time, an arrival time
1298 /// or a rate extrapolated forward. Nothing here can express one, which is
1299 /// deliberate — the only input is a share of a measured payload.
1300 ///
1301 /// # Sizes, and the deferral rule
1302 ///
1303 /// `progress_rules` emits the tones and never the width, because the width is
1304 /// not this crate's to know. A pseudo-element has no intrinsic size at all, so
1305 /// the same treatment would render nothing anywhere. Both sizes are therefore
1306 /// custom properties with defaults: an app that wants a different mark sets
1307 /// `--awaiting-mark` and `--awaiting-bar` once, and one that says nothing gets a
1308 /// mark that is visible.
1309 ///
1310 /// # The cadence, and what happens without it
1311 ///
1312 /// `--cadence-activity` comes from `makeover-timing` through `makeover-build`,
1313 /// and is a half-period, so a full cycle is twice it. It is used bare rather
1314 /// than with a fallback: a number written here would be a second heartbeat for
1315 /// a mark three renderers draw.
1316 ///
1317 /// A sheet assembled without the time axis leaves `animation-duration` invalid,
1318 /// which resolves to `0s`, which runs no animation and leaves the base style —
1319 /// a lit, still mark. That is also exactly what the reduced-motion block does,
1320 /// since it sets the cadence to `0ms`. Both fall out of one rule because the
1321 /// base style is lit and the keyframes do the dimming, which is the ordering
1322 /// `makeover_timing::reduced_motion_css` asks its consumers for by name.
1323 fn awaiting_rules(opts: &Emit) -> String {
1324 let mut css = String::new();
1325
1326 // Dimming rather than lighting, so a zero-length animation leaves a lit
1327 // mark rather than a blank one. See `makeover_timing::reduced_motion_css`.
1328 css.push_str(
1329 "@keyframes makeover-activity {\n \
1330 0%, 49.99% {\n background: var(--action);\n }\n \
1331 50%, 100% {\n background: var(--surface-sunken);\n }\n\
1332 }\n",
1333 );
1334
1335 // Nothing is drawn until something is waiting. `content` on the base rule
1336 // rather than on the busy one keeps the box the same box across the
1337 // transition, so a mark appearing does not reflow the line it is in.
1338 let _ = writeln!(
1339 css,
1340 "[data-awaiting]::after {{\n \
1341 content: \"\";\n \
1342 display: none;\n \
1343 margin-inline-start: var(--awaiting-gap, 0.5ch);\n \
1344 vertical-align: baseline;\n\
1345 }}"
1346 );
1347
1348 let _ = writeln!(
1349 css,
1350 "[data-awaiting][aria-busy=\"true\"]::after {{\n \
1351 display: inline-block;\n \
1352 inline-size: var(--awaiting-mark, 0.5em);\n \
1353 block-size: var(--awaiting-mark, 0.5em);\n \
1354 background: var(--action);\n \
1355 opacity: 1;\n \
1356 animation: makeover-activity calc(var(--cadence-activity) * 2) \
1357 step-end infinite;\n\
1358 }}"
1359 );
1360
1361 // The measured half. A wider box, no blink, and a gradient whose stop is
1362 // the share: the fill and the trough in one paint, so the markup stays one
1363 // pseudo-element on both branches.
1364 //
1365 // `--awaiting-share` unset is an empty trough, not a full one. A bar that
1366 // read full because nobody was counting would be the confidently-wrong
1367 // drawing rule 1 exists to forbid.
1368 //
1369 // The trough takes an edge for the reason a well does: a bar at zero share
1370 // is otherwise a rectangle of the surface it sits on, which is nothing at
1371 // all. `border_width` rather than a literal, the way `depth_rule` and
1372 // `track_rules` write theirs.
1373 let _ = writeln!(
1374 css,
1375 "[data-awaiting=\"determinate\"][aria-busy=\"true\"]::after {{\n \
1376 inline-size: var(--awaiting-bar, 6em);\n \
1377 animation: none;\n \
1378 outline: {} solid var(--border);\n \
1379 outline-offset: -{};\n \
1380 background: linear-gradient(\n \
1381 to inline-end,\n \
1382 var(--action) 0 calc(var(--awaiting-share, 0) * 100%),\n \
1383 var(--surface-sunken) 0\n \
1384 );\n\
1385 }}",
1386 opts.border_width, opts.border_width
1387 );
1388
1389 css
1390 }
1391
1392 /// A strip of figures, and the two spans inside each one.
1393 ///
1394 /// Colour only, which is the deferral rule applied to a component that badly
1395 /// wants to break it. A figure reads as a figure because the value is set large
1396 /// over a small caption, and that is a size: `makeover-geometry` answers how
1397 /// much space and this crate answers what the thing is. Emitting `font-size`
1398 /// here would be this crate naming a value, which is the one thing it is defined
1399 /// by not doing, and `progress_rules` is the precedent — it emits the tones and
1400 /// never the width, because the width is not its to know.
1401 ///
1402 /// So the arrangement and the type scale are the app's, and what is generated is
1403 /// the part an app cannot get right by itself: which of the two spans carries
1404 /// the tone.
1405 fn figure_rules(opts: &Emit) -> String {
1406 let figure = class("figure", opts);
1407 let value = class("figure-value", opts);
1408 let caption = class("figure-caption", opts);
1409 let change = class("figure-change", opts);
1410 let mut css = String::new();
1411
1412 let _ = writeln!(
1413 css,
1414 ".{figure} > .{value} {{\n color: var(--{});\n}}",
1415 Tone::Neutral.token()
1416 );
1417 let _ = writeln!(
1418 css,
1419 ".{figure} > .{caption} {{\n color: var(--content-muted);\n}}"
1420 );
1421 let _ = writeln!(
1422 css,
1423 ".{figure} > .{change} {{\n color: var(--content-muted);\n}}"
1424 );
1425
1426 // A toned figure tones one part and never the caption. The caption is the
1427 // noun and stays muted.
1428 //
1429 // Which part depends on whether there is a change, and that is the whole of
1430 // what 0.13.0 changed here. A figure with a delta is an ordinary number that
1431 // has moved in a direction worth reading, so the delta takes the colour and
1432 // the number stays plain; a figure without one has nowhere else to put it.
1433 // `:has` is what lets one attribute mean both, and the alternative was the
1434 // emitter deciding by writing the attribute onto a different element, which
1435 // leaves two elements able to disagree about a figure's one meaning.
1436 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
1437 let _ = writeln!(
1438 css,
1439 ".{figure}[data-tone=\"{0}\"] > .{change} {{\n color: var(--{0});\n}}",
1440 tone.token()
1441 );
1442 let _ = writeln!(
1443 css,
1444 ".{figure}[data-tone=\"{0}\"]:not(:has(> .{change})) > .{value} \
1445 {{\n color: var(--{0});\n}}",
1446 tone.token()
1447 );
1448 }
1449 css
1450 }
1451
1452 /// A picture, its frame and its caption.
1453 ///
1454 /// `makeover_layout::Image` arrived at 0.21.0, found by trying to describe MNW's
1455 /// carousel and discovering nothing named a picture.
1456 ///
1457 /// # The frame is a border, and this is the one place a bevel is wrong
1458 ///
1459 /// 0.36.0 emitted [`Depth::Raised`] here through [`depth_rule`], the same call
1460 /// `button` and `card` make. It was wrong, and MNW's landing page is where it
1461 /// showed: **the frames had no visible edge at all.**
1462 ///
1463 /// `Depth::Raised`'s edge is `--bevel-raised`, which is an *inset* shadow — a
1464 /// 1px light run at the top-left and a dark one at the bottom-right, drawn
1465 /// **inside** the element's box. On a button or a card that box is a surface
1466 /// this crate owns, so an inset edge reads as the surface catching the light.
1467 /// On a picture it is drawn on top of the picture, over whatever pixels the
1468 /// image happens to have at its border. MNW's screenshots are light-on-light
1469 /// parchment, so the light half landed on a light image and the frame
1470 /// disappeared.
1471 ///
1472 /// **You cannot bevel a surface you do not own.** A picture's content is the
1473 /// app's, arrives at request time, and can be any colour, so its edge has to
1474 /// sit *outside* the content rather than on it. That is a border.
1475 ///
1476 /// The fill stays, and it is not decoration: it is what shows through a
1477 /// transparent PNG and what stands in the frame's place while the image is
1478 /// still loading.
1479 ///
1480 /// This is a real limit on [`Depth`] rather than a special case. Every other
1481 /// consumer of a depth draws its own surface; a picture is the first member
1482 /// whose surface belongs to someone else.
1483 ///
1484 /// # No size
1485 ///
1486 /// `width: 100%` and nothing else. How large a picture is depends on the box it
1487 /// was put in, which is the app's arrangement and `makeover-geometry`'s scales,
1488 /// and a renderer that picked one would be answering for every consumer at
1489 /// once. This is where `figure_rules` landed for the same reason.
1490 fn picture_rules(opts: &Emit) -> String {
1491 let picture = class("picture", opts);
1492 let img = class("picture-img", opts);
1493 let caption = class("picture-caption", opts);
1494 let mut css = String::new();
1495
1496 // Block, or an inline image sits on the text baseline and carries a
1497 // descender's worth of space under it that no app ever wants and every app
1498 // deletes by hand. The border is the frame; see the type docs for why it is
1499 // not the bevel every other surface here gets.
1500 let _ = writeln!(
1501 css,
1502 ".{img} {{\n display: block;\n width: 100%;\n height: auto;\n \
1503 background: var(--{});\n border: {} solid var(--border);\n}}",
1504 Fill::Raised.token(),
1505 opts.border_width
1506 );
1507
1508 // The two fits that need a rule. `Fit::Natural` emits no attribute at all,
1509 // so it is the bare rule above and needs nothing here.
1510 let _ = writeln!(
1511 css,
1512 ".{img}[data-fit=\"cover\"] {{\n height: 100%;\n object-fit: cover;\n}}"
1513 );
1514 let _ = writeln!(
1515 css,
1516 ".{img}[data-fit=\"contain\"] {{\n height: 100%;\n object-fit: contain;\n}}"
1517 );
1518
1519 // A caption reads back one step, which is `figure-caption`'s answer and the
1520 // same claim: it says what the thing above it is, and it is not the thing.
1521 let _ = writeln!(
1522 css,
1523 ".{picture} > .{caption} {{\n color: var(--content-muted);\n}}"
1524 );
1525
1526 css
1527 }
1528
1529 /// A region showing one child at a time, and the chrome that moves between them.
1530 ///
1531 /// [`makeover_layout::Showing`] lets a description say that a region holds
1532 /// several children and shows some of them. A renderer derives its own chrome
1533 /// from that, which is what stops every renderer growing a `match` on a widget
1534 /// name; these are the rules the derived chrome needs.
1535 ///
1536 /// # Why the default is every child, and the enhancement takes them away
1537 ///
1538 /// The controls are a lie until something binds them. A prev button rendered
1539 /// into a document with no script is a control that looks live and answers
1540 /// nothing, and the reader it lies to is exactly the one who cannot see the
1541 /// other children either — the collapsing and the moving are the same half.
1542 ///
1543 /// So the rules run in the direction the enhancement does. Nothing here hides a
1544 /// child and nothing here shows a control. Whatever binds the region sets
1545 /// `data-ready` on it, and that is what collapses the stack to one and reveals
1546 /// the row that moves it. A reader with no script gets every child in order and
1547 /// no controls, which is more content rather than less, and a reader with
1548 /// script gets a settled page rather than a stack that jumps to one frame after
1549 /// load.
1550 ///
1551 /// MNW proved this shape by hand — a `<noscript>` stylesheet opening its
1552 /// carousel back out — and it is here rather than there because the property is
1553 /// the description's, not one app's.
1554 ///
1555 /// # Not spacing
1556 ///
1557 /// The row's gaps are `makeover-geometry`'s question and are absent for
1558 /// [`row_rules`]'s reason. What is here is `display`, which carries no
1559 /// magnitude, and the muted readout, which is the same claim `picture-caption`
1560 /// makes: it says where you are among the children and it is not one of them.
1561 fn showing_rules(opts: &Emit) -> String {
1562 let controls = class("showing", opts);
1563 let position = class("showing-position", opts);
1564 let frame = class("showing-frame", opts);
1565 let mut css = String::new();
1566
1567 // Hidden until something binds it, which is the whole argument above.
1568 let _ = writeln!(css, ".{controls} {{\n display: none;\n}}");
1569 // Block, and nothing about how the three sit in it. A button and a span are
1570 // inline already, so they make a row without this crate saying so, and
1571 // saying so is where `align-items` and a gap would follow -- both spacing,
1572 // both `makeover-geometry`'s, and `row_rules` refuses them for the same
1573 // reason.
1574 let _ = writeln!(
1575 css,
1576 "[data-ready] > .{controls} {{\n display: block;\n}}"
1577 );
1578
1579 // A child is in flow until the region is bound, and then only the current
1580 // one is. `.current` is a modifier for the reason `.chosen` and `.latched`
1581 // are: one name for the state, set by whoever knows it.
1582 let _ = writeln!(
1583 css,
1584 "[data-ready] > .{frame}:not(.current) {{\n display: none;\n}}"
1585 );
1586
1587 // Reads back one step. `picture-caption`'s rule and its reason.
1588 let _ = writeln!(css, ".{position} {{\n color: var(--content-muted);\n}}");
1589
1590 css
1591 }
1592
1593 /// A time axis: the container, its gridlines and ruler, and the placed things.
1594 ///
1595 /// `makeover-layout` 0.24.0's [`Track`](makeover_layout::Track), and the first
1596 /// member here whose whole point is *position*. That makes the magnitude line
1597 /// this crate keeps worth restating rather than assuming.
1598 ///
1599 /// # Where the numbers come from
1600 ///
1601 /// Every value that varies per item is a custom property the caller sets
1602 /// inline, and every rule here reads one. `--track-at` and `--track-for` are
1603 /// percentages of the span, which
1604 /// [`Track::fraction`](makeover_layout::Track::fraction) computes once so three
1605 /// renderers cannot disagree about it. Nothing here knows a pixel.
1606 ///
1607 /// That is what lets the stylesheet stay static while the items move: an entry
1608 /// carries `style="--track-at: 37.5%; --track-for: 4.166%"` and the rule below
1609 /// turns it into a box. The alternative was emitting a rule per item, which is
1610 /// a stylesheet that grows with the data.
1611 ///
1612 /// **The height of the track is the app's**, not this crate's. 96 quarter-hour
1613 /// slots at some slot height is a size, and a size is `makeover-geometry`'s
1614 /// question -- the same refusal `figure_rules` and `placeholder_rules` make.
1615 /// Percentages need a resolved height above them, so `.track` gets
1616 /// `position: relative` and nothing else; the app says how tall a day is.
1617 ///
1618 /// # Overlap
1619 ///
1620 /// Two things at the same time is intrinsic to an axis and has no analogue in a
1621 /// list. The description does not declare it -- `Placement::overlaps` derives it
1622 /// from the times -- so what arrives here is a lane index and a lane count, and
1623 /// the rule divides the width. A renderer that would rather stack them ignores
1624 /// both properties and the defaults give it one full-width lane.
1625 fn track_rules(opts: &Emit) -> String {
1626 let track = class("track", opts);
1627 let slot = class("track-slot", opts);
1628 let tick = class("track-tick", opts);
1629 let entry = class("track-entry", opts);
1630 let mut css = String::new();
1631
1632 // The positioning context every entry resolves against, and the whole of
1633 // what this crate says about the container. No height: see the doc above.
1634 let _ = writeln!(css, ".{track} {{\n position: relative;\n}}");
1635
1636 // Gridlines and the ruler are the axis reading itself back, which is
1637 // `picture-caption` and `showing-position`'s claim: about the thing rather
1638 // than one of the things.
1639 //
1640 // `border_width` rather than a literal, the way `depth_rule` writes its
1641 // edge. A gridline is the one place a timeline would most naturally reach
1642 // for a hardcoded 1px, and a hardcoded 1px is this crate naming a size.
1643 let _ = writeln!(
1644 css,
1645 ".{slot} {{\n border-top: {} solid var(--border);\n}}",
1646 opts.border_width
1647 );
1648 let _ = writeln!(css, ".{tick} {{\n color: var(--content-muted);\n}}");
1649
1650 // The one rule that does real work. Top and height are the placement;
1651 // left and width are the lane. Both lane properties default so an entry
1652 // that names neither is full width, which is the common case and the one a
1653 // renderer gets for free.
1654 let _ = writeln!(
1655 css,
1656 ".{entry} {{\n \
1657 position: absolute;\n \
1658 top: var(--track-at, 0%);\n \
1659 height: var(--track-for, 100%);\n \
1660 left: calc(var(--track-lane, 0) / var(--track-lanes, 1) * 100%);\n \
1661 width: calc(100% / var(--track-lanes, 1));\n\
1662 }}"
1663 );
1664
1665 css
1666 }
1667
1668 /// A region's stand-in, and the header of a table that can be reordered.
1669 ///
1670 /// Both are 0.12.0 members and both are colour and affordance only, which is
1671 /// where `figure_rules` landed after trying to emit a type scale. How much room
1672 /// a stand-in gets is a size — goingson has the same one at three, as
1673 /// `--compact`, `--dashboard` and `--padded` — and a size is
1674 /// `makeover-geometry`'s question.
1675 ///
1676 /// The caret is the one thing here that is neither colour nor affordance, and it
1677 /// is a renderer's own expression rather than a value the description named:
1678 /// `aria-sort` is what the table actually says, and this turns it into something
1679 /// visible for everyone not using a screen reader. A terminal draws its own; an
1680 /// immediate-mode painter draws its own.
1681 fn state_rules(opts: &Emit) -> String {
1682 let placeholder = class("placeholder", opts);
1683 let text = class("placeholder-text", opts);
1684 let heading = class("table-heading", opts);
1685 let mut css = String::new();
1686
1687 let _ = writeln!(
1688 css,
1689 ".{placeholder} > .{text} {{\n color: var(--content-muted);\n}}"
1690 );
1691 // Only the failure is toned. An empty list is the normal state of a new
1692 // install, and `Readiness::tone` is what says so.
1693 let _ = writeln!(
1694 css,
1695 ".{placeholder}[data-tone=\"{0}\"] > .{text} {{\n color: var(--{0});\n}}",
1696 Tone::Danger.token()
1697 );
1698
1699 // A header that reorders the table is a control, and the pointer is the
1700 // only part of saying so that is not the app's own type and spacing.
1701 let _ = writeln!(
1702 css,
1703 ".{heading}[data-sortable] {{\n cursor: pointer;\n}}"
1704 );
1705 // The caret carries its own leading space, the way `makeover-tui` and
1706 // `makeover-immediate` both write `" \u{25B2}"`. It used to be emitted bare,
1707 // and both apps that adopted the vocabulary had to put the gap back in their
1708 // own stylesheets on the same afternoon -- each having to work out first that
1709 // app CSS outranks this crate's cascade layer, so adding the space the
1710 // obvious way, as `content`, silently wins over the glyph and leaves the
1711 // heading with no caret at all. A consumer should not have to know that, and
1712 // with the space emitted here there is nothing left for one to add.
1713 //
1714 // Three states, three tones, on the convention in wiki
1715 // `three-tone-convention`. A column in force is `content`; a column offering
1716 // to reorder and not doing it now is `content-secondary`, because it still
1717 // answers a press; a column that is not sortable emits no caret at all and
1718 // takes nothing. The idle arm used to hide its glyph and reserve the box,
1719 // which cost a reflow-free press and said nothing. It draws now, and the
1720 // reservation stops being a thing to get right.
1721 //
1722 // The glyph is `Sort::glyph`, escaped rather than written: a CSS `content`
1723 // string cannot carry the character literally through this file's own
1724 // escaping, and spelling it here as well would put the third copy back that
1725 // `makeover-layout` 0.27.5 exists to remove.
1726 let _ = writeln!(
1727 css,
1728 ".{heading}[data-sortable]::after \
1729 {{\n content: \" {}\";\n color: var(--content-secondary);\n}}",
1730 css_escape(Sort::Ascending.glyph())
1731 );
1732 for direction in [Sort::Ascending, Sort::Descending] {
1733 let _ = writeln!(
1734 css,
1735 ".{heading}[aria-sort=\"{}\"]::after \
1736 {{\n content: \" {}\";\n color: var(--content);\n}}",
1737 direction.as_str(),
1738 css_escape(direction.glyph())
1739 );
1740 }
1741 css
1742 }
1743
1744 /// The frame a table sits in.
1745 ///
1746 /// # Why this is a CSS table and not the grid the rest of the module assumes
1747 ///
1748 /// A grid row needs `grid-template-columns`, which has to name every column in
1749 /// order, so it cannot be written without knowing the columns. That is what
1750 /// [`list::narrowing_css`] is for, and it works: goingson builds `tables.css` in
1751 /// its own `build.rs` out of it, and nothing here changes that.
1752 ///
1753 /// It does not work for a table a *description* produced. Those columns are
1754 /// known at render time rather than at build time, and the rules would have to
1755 /// travel with the markup: a `<style>` element per table, which needs
1756 /// `style-src 'unsafe-inline'` and so blocks the MNW server's standing plan to
1757 /// drop it. The head is not an escape: a table swapped in by htmx after a
1758 /// delete arrives as a fragment with no head at all.
1759 ///
1760 /// A CSS table aligns its columns across rows knowing nothing about how many
1761 /// there are, so there is no track list to emit and nothing per-table to carry.
1762 /// The cost is that a described table cannot take a per-column fixed length,
1763 /// which costs nothing today: [`Sizing`](list::Sizing) is looked up by column
1764 /// name and a description carries no lengths to put in it, so every track a
1765 /// described table could ask for is already content, fill or auto.
1766 ///
1767 /// [`Priority`] hiding is unchanged in kind. It moves from a generated
1768 /// `display: none` per dropped column to one rule per drop class, which is the
1769 /// same fact addressed by class rather than by cutoff, and still never by
1770 /// position.
1771 fn table_rules(opts: &Emit) -> String {
1772 let table = class("table", opts);
1773 let head = class("table-head", opts);
1774 let row = class("table-row", opts);
1775 let heading = class("table-heading", opts);
1776 let cell = class("cell", opts);
1777 let mut css = String::new();
1778
1779 let _ = writeln!(
1780 css,
1781 ".{table} {{\n display: table;\n width: 100%;\n}}"
1782 );
1783 let _ = writeln!(css, ".{head},\n.{row} {{\n display: table-row;\n}}");
1784 let _ = writeln!(css, ".{heading},\n.{cell} {{\n display: table-cell;\n}}");
1785
1786 // A content column shrinks to what is in it. `width: 1%` is how a CSS table
1787 // is told that: auto layout hands the slack to the columns that asked for
1788 // room, and a column asking for almost none gets what it needs and no more.
1789 // The `nowrap` is what stops it being given less by wrapping.
1790 let _ = writeln!(
1791 css,
1792 ".{} {{\n white-space: nowrap;\n width: 1%;\n}}",
1793 class("cell-content", opts)
1794 );
1795
1796 // A fixed column has no length to be fixed to. The description carries none
1797 // and `Sizing` is not reachable from here, so it behaves as content: the
1798 // honest answer to a width nobody supplied, and the same one `Sizing::track`
1799 // gives it.
1800 let _ = writeln!(
1801 css,
1802 ".{} {{\n white-space: nowrap;\n}}",
1803 class("cell-fixed", opts)
1804 );
1805
1806 // Optional columns go at the narrowest class, secondary ones go with them,
1807 // which is the cutoff walk `kept_at` describes said as two media queries.
1808 // Essential columns have no rule at all, because never dropping is what not
1809 // being mentioned already means.
1810 for (size, drops) in [
1811 (
1812 SizeClass::Compact,
1813 &["cell-drops-first", "cell-drops-next"][..],
1814 ),
1815 (SizeClass::Medium, &["cell-drops-first"][..]),
1816 ] {
1817 let selectors: Vec<String> = drops
1818 .iter()
1819 .map(|drop| format!(".{}", class(drop, opts)))
1820 .collect();
1821 css.push_str(&gated(
1822 Some(&size.media_condition()),
1823 &format!("{} {{\n display: none;\n}}\n", selectors.join(",\n")),
1824 ));
1825 }
1826
1827 // What is inside a cell, which the table side could not say until
1828 // makeover-layout 0.14.0. Every cell was one `.cell` and one content
1829 // colour, so a button in a cell was painted as text -- the drift
1830 // `RowPart::intent` has prevented for list rows since 0.2.0 and prevented
1831 // for nothing here.
1832 //
1833 // The colour goes on `.cell-value` rather than on `.cell`, and that
1834 // placement is the whole fix. On the container it would cascade into the
1835 // tokens and the controls sitting beside the text, which is the bug said
1836 // in one rule; on the part that is text, it reaches text and stops.
1837 for part in [
1838 CellPart::Value,
1839 CellPart::Tokens,
1840 CellPart::Actions,
1841 CellPart::Link,
1842 ] {
1843 // Three of the four inherit, each for its own reason: a token carries
1844 // its own tone, an action is a control rather than text, and a link
1845 // takes the action colour from the anchor it is. `CellPart::intent`
1846 // says so by answering with the intent inheriting already gives, and
1847 // pinning that would be louder than saying nothing.
1848 //
1849 // Written as a skip-list rather than as a match on Value, so a member
1850 // added upstream gets its intent emitted rather than being silently
1851 // dropped. That is the same trade `part_class`'s fallback makes: land
1852 // plainly, never land as nothing.
1853 if !matches!(part, CellPart::Tokens | CellPart::Actions | CellPart::Link) {
1854 let _ = writeln!(
1855 css,
1856 ".{} {{\n color: var(--{});\n}}",
1857 class(cell_part_class(part), opts),
1858 part.intent()
1859 );
1860 }
1861 }
1862
1863 css
1864 }
1865
1866 /// The component layer: every named thing phase A emits.
1867 ///
1868 /// No scrollbar track. It was on the phase A list and came off: eight lines of
1869 /// `::-webkit-scrollbar` with no shape a terminal or an immediate-mode painter
1870 /// would want handed to it, so it stays with the apps.
1871 #[must_use]
1872 pub fn component_rules(opts: &Emit) -> String {
1873 let mut css = String::new();
1874 css.push_str(&surface_rules(opts));
1875 css.push_str(&link_rules(opts));
1876 css.push_str(&token_rules(opts));
1877 css.push_str(&selector_rules(opts));
1878 css.push_str(&row_rules(opts));
1879 css.push_str(&run_rules(opts));
1880 css.push_str(&progress_rules(opts));
1881 css.push_str(&awaiting_rules(opts));
1882 css.push_str(&figure_rules(opts));
1883 css.push_str(&picture_rules(opts));
1884 css.push_str(&showing_rules(opts));
1885 css.push_str(&track_rules(opts));
1886 css.push_str(&state_rules(opts));
1887 css.push_str(&table_rules(opts));
1888 css.push_str(&facet::facet_rules(opts));
1889 css.push_str(&form::editor_rules(opts));
1890 css.push_str(&form::suggestion_rules(opts));
1891 css.push_str(&form::unit_rules(opts));
1892 css
1893 }
1894
1895 /// The whole phase-A stylesheet: properties, depth rules and components, in
1896 /// [`CSS_LAYER`], under a generated-file banner.
1897 ///
1898 /// The banner sits outside the layer, because a comment participates in no
1899 /// cascade and a reader opening the file should see what it is before seeing
1900 /// an at-rule.
1901 #[must_use]
1902 pub fn stylesheet(opts: &Emit) -> String {
1903 let body = in_css_layer(&format!(
1904 ":root {{\n{}}}\n\n{}\n{}",
1905 bevel_properties(opts),
1906 depth_rules(opts),
1907 component_rules(opts)
1908 ));
1909 // Counted from the body rather than through `vocabulary::names`, which
1910 // calls back into here.
1911 let classes = vocabulary::classes_in_css(&body).len();
1912 let version = VERSION;
1913 format!(
1914 "/* Generated by makeover-webview {version} from makeover-layout, \
1915 {classes} classes.\n \
1916 Do not edit. The version and the count are here because a stale\n \
1917 lockfile fails silently: an older emitter writes a well-formed sheet\n \
1918 with components missing, and nothing else in the file says so. If\n \
1919 this version trails what the manifest asks for, re-resolve.\n\n \
1920 Depth is a fill and an edge together; naming them apart is what let\n \
1921 them disagree. See the crate's README and wiki note makeover-layout.\n\n \
1922 Everything below is in the `{CSS_LAYER}` cascade layer. Declare the\n \
1923 order once in your own stylesheet, or this layer's position is decided\n \
1924 by whichever generated file the browser happens to see first:\n\n \
1925 @layer {CSS_LAYER}, base, components, responsive; */\n{body}"
1926 )
1927 }
1928
1929 #[cfg(test)]
1930 mod tests {
1931 use super::*;
1932 use makeover_layout::Edge;
1933
1934 #[test]
1935 fn every_fallback_class_is_one_a_checker_knows_about() {
1936 // The obligation ROW_PART_CLASSES carries, for the same reason: a class
1937 // this crate can write and the vocabulary list does not carry is
1938 // invisible to the dead-vocabulary seal and to the overlap check both.
1939 for fallback in [
1940 Fallback::Wrap,
1941 Fallback::Stack,
1942 Fallback::Shed,
1943 Fallback::Menu,
1944 ] {
1945 assert!(
1946 RUN_CLASSES.contains(&fallback_class(fallback)),
1947 "{fallback:?} is missing from RUN_CLASSES"
1948 );
1949 }
1950 let names = crate::vocabulary::names(&Emit::default());
1951 for name in RUN_CLASSES {
1952 assert!(names.contains(*name), "{name} is not in the vocabulary");
1953 }
1954 }
1955
1956 #[test]
1957 fn a_run_gives_every_member_a_floor_it_cannot_be_squeezed_below() {
1958 // The whole of what stops the overlap, and it is not a fallback: it
1959 // applies to every run whatever the group declared. flexbox's default
1960 // min-width is auto, which lets an item be compressed below its own
1961 // content in a nowrap row, and that is how a toolbar is drawn over a
1962 // tab strip even with nothing out of flow.
1963 let css = run_rules(&Emit::default());
1964 assert!(css.contains(".run > * {\n min-width: min-content;\n}"));
1965 // No number anywhere in it. The minimum is derived by the browser from
1966 // what the members contain, which is the ruling's own requirement.
1967 assert!(!css.contains("px"));
1968 assert!(!css.contains("rem"));
1969 assert!(!css.contains("@media"));
1970 }
1971
1972 #[test]
1973 fn room_is_never_asked_of_the_viewport() {
1974 // The 913 case: a window in SizeClass::Expanded holding a group out of
1975 // room. A viewport query answers about the window and would be wrong
1976 // about the group, which is why the table's @media walk is not the
1977 // precedent this follows.
1978 let css = run_rules(&Emit::default());
1979 for size in [SizeClass::Compact, SizeClass::Medium] {
1980 assert!(!css.contains(&size.media_condition()));
1981 }
1982 }
1983
1984 #[test]
1985 fn every_fallback_lands_as_a_class_and_an_unknown_one_lands_plainly() {
1986 let css = run_rules(&Emit::default());
1987 for fallback in [
1988 Fallback::Wrap,
1989 Fallback::Stack,
1990 Fallback::Shed,
1991 Fallback::Menu,
1992 ] {
1993 let class = fallback_class(fallback);
1994 assert!(css.contains(&format!(".{class} {{")), "{class} unemitted");
1995 }
1996 // Stack is the one that also says what a member does with the line it
1997 // took, which is what separates it from wrapping.
1998 assert!(css.contains(".run-stack > * {\n flex: 1 1 max-content;\n}"));
1999 }
2000
2001 #[test]
2002 fn the_emitted_bevel_matches_what_the_apps_already_hand_write() {
2003 // Balanced Breakfast's styles.css, verbatim. Adoption has to be a
2004 // deletion, not a redesign, or nobody will take it.
2005 let opts = Emit::default();
2006 assert_eq!(
2007 bevel_shadow(Bevel::Raised, &opts),
2008 "inset 1px 1px 0 var(--bevel-light), inset -1px -1px 0 var(--bevel-dark)"
2009 );
2010 assert_eq!(
2011 bevel_shadow(Bevel::Inset, &opts),
2012 "inset 1px 1px 0 var(--bevel-dark), inset -1px -1px 0 var(--bevel-light)"
2013 );
2014 }
2015
2016 #[test]
2017 fn no_colour_ever_reaches_the_output() {
2018 let css = stylesheet(&Emit::default());
2019 assert!(!css.contains('#'), "a hex literal escaped into the CSS");
2020 assert!(
2021 !css.contains("rgb"),
2022 "a colour function escaped into the CSS"
2023 );
2024 // Every colour is named, never resolved.
2025 assert!(css.contains("var(--surface-raised)"));
2026 assert!(css.contains("var(--bevel-light)"));
2027 }
2028
2029 #[test]
2030 fn a_well_falls_back_through_css_rather_than_through_rust() {
2031 assert_eq!(
2032 fill_var(Fill::Well),
2033 "var(--surface-well, var(--surface-page))"
2034 );
2035 // Nothing else needs one.
2036 assert_eq!(fill_var(Fill::Raised), "var(--surface-raised)");
2037 assert_eq!(fill_var(Fill::Page), "var(--surface-page)");
2038 }
2039
2040 #[test]
2041 fn raised_and_well_do_not_collapse_onto_each_other() {
2042 let css = depth_rules(&Emit::default());
2043 assert!(css.contains(".raised {"));
2044 assert!(css.contains(".well {"));
2045 assert!(css.contains("var(--bevel-raised)"));
2046 assert!(css.contains("var(--bevel-inset)"));
2047 }
2048
2049 /// The cast shadow is composed here from the tone `makeover` derives, so
2050 /// neither crate has to hold the other's numbers.
2051 ///
2052 /// It is a `:root` property and deliberately not a depth class. There is no
2053 /// `Depth::Overlay` in the description layer, and adding one would be a
2054 /// claim about what a screen means rather than about how it is painted;
2055 /// until something asks for it, a consumer names the property on the rule
2056 /// for the menu or the toast it already has.
2057 #[test]
2058 fn the_cast_shadow_is_a_root_property_not_a_depth() {
2059 let css = bevel_properties(&Emit::default());
2060 assert!(css.contains("--elevation-overlay:"));
2061 assert!(css.contains("var(--elevation)"));
2062 assert!(
2063 !depth_rules(&Emit::default()).contains("elevation"),
2064 "elevation is not a depth class"
2065 );
2066 }
2067
2068 #[test]
2069 fn the_cascade_carries_the_pressed_state() {
2070 let css = surface_rules(&Emit::default());
2071 // The one thing this renderer gets free that the other two resolve by
2072 // hand, eighteen call sites deep in audiofiles' case. Asserted on a
2073 // named surface: pressing belongs to the control, not to the depth.
2074 assert!(css.contains(".card:active {"));
2075 assert!(css.contains(".button:active {"));
2076 }
2077
2078 #[test]
2079 fn the_depth_class_is_a_surface_and_not_a_control() {
2080 let css = depth_rules(&Emit::default());
2081 // The static surface the vocabulary was missing. Sixteen goingson
2082 // elements wore .card and cancelled its hover and press to get this,
2083 // because a raised object that is not pressable had no other spelling.
2084 for state in [":hover", ":active", ":focus-visible", ":disabled"] {
2085 assert!(
2086 !css.contains(&format!(".raised{state}")),
2087 "the depth class claimed {state}: {css}"
2088 );
2089 }
2090 assert!(css.contains("var(--bevel-raised)"), "still raised: {css}");
2091 }
2092
2093 #[test]
2094 fn pressing_moves_the_fill_and_not_only_the_edge() {
2095 // The decision-1 guard, and the regression that mattered: emitting the
2096 // bevel flip alone is what left goingson hand-writing `background:
2097 // var(--surface-sunken)` on .btn, .card and .tag/.badge alike, so none
2098 // of the three could be deleted.
2099 let pressed = interactive_rules("button", Depth::Raised, &Emit::default());
2100 assert!(pressed.contains(".button:active {"));
2101 assert!(
2102 pressed.contains("background: var(--surface-well, var(--surface-page))"),
2103 "pressed dropped its fill: {pressed}"
2104 );
2105 assert!(pressed.contains("box-shadow: var(--bevel-inset)"));
2106 }
2107
2108 #[test]
2109 fn pressed_takes_its_fill_from_the_description_not_from_the_app() {
2110 // goingson presses to --surface-sunken. The description says a pressed
2111 // raised region reads as a well, and makeover says outright that
2112 // surface-sunken cannot serve as one, so the app is the thing that
2113 // moves.
2114 //
2115 // Scoped to the pressed rules rather than to the whole sheet: since
2116 // makeover-layout 0.3.0 an unchosen tab is legitimately
2117 // --surface-sunken, so the token appearing somewhere in the output no
2118 // longer means the app's choice leaked in.
2119 let css = stylesheet(&Emit::default());
2120 let mut checked = 0;
2121 for rule in css.split("}\n") {
2122 if !rule.contains(":active") {
2123 continue;
2124 }
2125 checked += 1;
2126 assert!(
2127 !rule.contains("surface-sunken"),
2128 "a pressed rule took the app's fill: {rule}"
2129 );
2130 }
2131 assert!(checked > 0, "no pressed rules found to check");
2132 assert_eq!(
2133 Depth::Raised.pressed().fill(),
2134 Some(Fill::Well),
2135 "the description changed under us"
2136 );
2137 }
2138
2139 #[test]
2140 fn the_whole_stylesheet_is_emitted_in_the_family_layer() {
2141 // The point of 0.11.0. Unlayered normal declarations outrank every
2142 // named layer, so an app declaring `@layer base, components` loses
2143 // every rule it owns to this file until this file is layered too.
2144 let css = stylesheet(&Emit::default());
2145 assert!(css.contains(&format!("@layer {CSS_LAYER} {{")));
2146
2147 // Exactly one layer block, and nothing outside it but the banner.
2148 assert_eq!(css.matches("@layer").count(), 2, "banner names it once");
2149 let opened = css.find("@layer makeover {").expect("layer opens");
2150 for (i, line) in css.lines().enumerate() {
2151 let before_layer = css.lines().take(i).map(str::len).sum::<usize>() < opened;
2152 if before_layer || line.is_empty() {
2153 continue;
2154 }
2155 assert!(
2156 line.starts_with(" ") || line == "}" || line.starts_with(" "),
2157 "line outside the layer: {line:?}"
2158 );
2159 }
2160 }
2161
2162 #[test]
2163 fn the_generated_sheet_carries_no_trailing_whitespace() {
2164 // A checked-in generated file that a formatter wants to rewrite is a
2165 // diff every time somebody saves it.
2166 let css = stylesheet(&Emit::default());
2167 for (i, line) in css.lines().enumerate() {
2168 assert_eq!(line, line.trim_end(), "trailing whitespace on line {i}");
2169 }
2170 }
2171
2172 #[test]
2173 fn the_banner_tells_an_app_how_to_order_the_layer() {
2174 // Without a declared order the layer's position depends on which
2175 // generated file the browser sees first, which is not a contract.
2176 let css = stylesheet(&Emit::default());
2177 assert!(css.contains("@layer makeover, base, components, responsive;"));
2178 // And the banner is outside the layer, not a rule inside it.
2179 assert!(css.starts_with("/* Generated by makeover-webview"));
2180 }
2181
2182 #[test]
2183 fn the_banner_names_the_emitter_so_a_stale_pin_is_visible_on_sight() {
2184 // A consumer whose lockfile pins an old version gets a well-formed
2185 // sheet with components missing and no error. balanced_breakfast ran
2186 // on 657 bytes from a 0.1.0 emitter while its manifest asked for
2187 // 0.5.1, and the only way it surfaced was diffing two apps' generated
2188 // files. The version and the count are what the file says instead.
2189 let css = stylesheet(&Emit::default());
2190 let banner = css.lines().next().unwrap();
2191 assert!(
2192 banner.contains(VERSION),
2193 "{banner} does not name the emitter"
2194 );
2195 let classes = vocabulary::classes_in_css(&css).len();
2196 assert!(classes > 0);
2197 assert!(
2198 banner.contains(&format!("{classes} classes")),
2199 "{banner} does not carry the class count"
2200 );
2201 }
2202
2203 #[test]
2204 fn a_primitive_owns_every_state_it_implies() {
2205 // The whole point of 0.10.0. Anything emitting a hover rule owes the
2206 // other three, or the consuming app supplies them by out-specifying a
2207 // rule it does not own: 19 such rules in goingson, 21 in the MNW
2208 // server, and three focus rings that do not match.
2209 let css = stylesheet(&Emit::default());
2210 for selector in ["button", "card", "chip", "tab", "segment", "toggle"] {
2211 assert!(css.contains(&format!(".{selector}:hover {{")), "{selector}");
2212 assert!(
2213 css.contains(&format!(".{selector}:active {{")),
2214 "{selector}"
2215 );
2216 assert!(
2217 css.contains(&format!(".{selector}:focus-visible {{")),
2218 "{selector} has no focus ring"
2219 );
2220 assert!(
2221 css.contains(&format!(".{selector}:disabled,")),
2222 "{selector} has no disabled state"
2223 );
2224 }
2225 }
2226
2227 #[test]
2228 fn a_field_takes_focus_and_refuses_input_without_taking_a_hover() {
2229 // A text field does not light up under the pointer, so it gets the two
2230 // states it has and not the two it does not.
2231 let css = stylesheet(&Emit::default());
2232 assert!(css.contains(".field:focus-visible {"));
2233 assert!(css.contains(".field:disabled,"));
2234 assert!(!css.contains(".field:hover {"));
2235 assert!(!css.contains(".field:active {"));
2236 }
2237
2238 #[test]
2239 fn disabled_is_emitted_after_hover_so_source_order_settles_it() {
2240 // Every one of these selectors is specificity (0,2,0), so nothing but
2241 // order decides which wins. A disabled button taking the hover fill is
2242 // the exact bug goingson's `.button:disabled:hover` was written to fix,
2243 // and the reason it had to reach (0,3,0) to do it.
2244 let css = interactive_rules("button", Depth::Raised, &Emit::default());
2245 let hover = css.find(":hover").expect("hover");
2246 let active = css.find(":active").expect("active");
2247 let focus = css.find(":focus-visible").expect("focus");
2248 let disabled = css.find(":disabled").expect("disabled");
2249 assert!(hover < active && active < focus && focus < disabled);
2250
2251 // And it restores the surface, or the hover fill survives underneath.
2252 let tail = &css[disabled..];
2253 assert!(tail.contains("background: var(--surface-raised)"));
2254 }
2255
2256 #[test]
2257 fn a_disabled_state_reaches_things_that_cannot_be_disabled() {
2258 // `:disabled` matches form elements only, and a chip is a div. Keying
2259 // on the ARIA attribute too is the pattern the invalid field already
2260 // set: one fact, read by the styling and the accessibility tree alike.
2261 let css = disabled_rule("chip", Depth::Raised);
2262 assert!(css.contains(".chip:disabled,"));
2263 assert!(css.contains(".chip[aria-disabled=\"true\"]"));
2264 assert!(css.contains("cursor: not-allowed"));
2265 }
2266
2267 #[test]
2268 fn the_focus_ring_does_not_disturb_the_bevel_it_lands_on() {
2269 // `outline` has its own property, so unlike the invalid ring there is
2270 // no bevel to restate beside it and nothing to keep in agreement.
2271 let opts = Emit::default();
2272 let css = focus_rule("button", Depth::Raised, &opts);
2273 assert!(css.contains("outline: 2px solid var(--focus-ring)"));
2274 assert!(!css.contains("box-shadow"), "the ring restated the bevel");
2275 }
2276
2277 #[test]
2278 fn a_well_takes_the_ring_inside_and_a_raised_surface_outside() {
2279 // One ring, placed by depth. The offset comes off `Depth::bevel` and
2280 // not off a per-component choice, which is what gave three apps three
2281 // different rings.
2282 let opts = Emit::default();
2283 assert!(focus_rule("field", Depth::Well, &opts).contains("outline-offset: calc(-1 * 2px)"));
2284 assert!(focus_rule("button", Depth::Raised, &opts).contains("outline-offset: 2px"));
2285 // Nothing to sit inside of, so it sits outside.
2286 assert!(focus_rule("badge", Depth::Sunken, &opts).contains("outline-offset: 2px"));
2287
2288 // And the ring is not the bevel. Reusing border_width emitted a 1px
2289 // ring that every consumer had already overridden.
2290 assert_ne!(opts.focus_width, opts.border_width);
2291 }
2292
2293 #[test]
2294 fn hover_is_gated_on_capability_and_the_keyboard_path_is_not() {
2295 // goingson's section 60 exists only to take back the hover state this
2296 // crate handed it. Gating at the source is what deletes that section
2297 // in all three apps rather than having each fight for it.
2298 let css = stylesheet(&Emit::default());
2299 let condition = format!("@media {}", Density::Pointer.media_condition());
2300 assert!(css.contains(&condition));
2301
2302 // What is gated is every hover state the surfaces carry. The row's
2303 // actions used to be the other half of this test and are not gated any
2304 // more, because they are not hidden any more: a rule that reveals
2305 // nothing needs no capability answer.
2306 let gated: Vec<&str> = css.lines().filter(|line| line.contains(":hover")).collect();
2307 assert!(!gated.is_empty(), "{css}");
2308 for line in gated {
2309 let indent = line.len() - line.trim_start().len();
2310 assert!(indent > 4, "an ungated hover rule: {line}");
2311 }
2312 assert!(!css.contains(".row:hover"), "{css}");
2313 }
2314
2315 #[test]
2316 fn the_capability_answer_is_asked_for_and_not_assumed() {
2317 // Both halves come from the crates that own them. If `makeover-touch`
2318 // ever says a fingertip has hover, this stops gating on its own.
2319 assert!(!Affordance::Hover.available(Density::Touch, SizeClass::Compact));
2320 assert!(Affordance::Hover.available(Density::Pointer, SizeClass::Compact));
2321 assert_eq!(hover_condition(), Some(Density::Pointer.media_condition()));
2322
2323 // And the size class passed to that call is not a claim about width.
2324 assert!(Affordance::Hover.reads_density());
2325 for size in [SizeClass::Compact, SizeClass::Medium, SizeClass::Expanded] {
2326 assert!(!Affordance::Hover.available(Density::Touch, size));
2327 }
2328 }
2329
2330 #[test]
2331 fn hover_resolves_against_the_token_makeover_already_derives() {
2332 let css = interactive_rules("card", Depth::Raised, &Emit::default());
2333 assert!(css.contains(".card:hover {"));
2334 assert!(css.contains("background: var(--hover-surface)"));
2335 // Not the app's choice, which was --surface-overlay.
2336 assert!(!css.contains("surface-overlay"));
2337 }
2338
2339 #[test]
2340 fn a_badge_gets_no_edge_and_no_fill() {
2341 // Decision 2, and the one visible redesign in phase A. Token::Badge is
2342 // Flat: an edge on a label says it can be pressed.
2343 let css = token_rules(&Emit::default());
2344 let badge = css
2345 .lines()
2346 .skip_while(|l| !l.starts_with(".badge {"))
2347 .take_while(|l| !l.starts_with('}'))
2348 .collect::<Vec<_>>()
2349 .join("\n");
2350 assert!(!badge.contains("box-shadow"), "badge kept an edge: {badge}");
2351 assert!(!badge.contains("background"), "badge kept a fill: {badge}");
2352 assert_eq!(Token::Badge.depth(false), Depth::Flat);
2353 assert_eq!(Token::Badge.depth(true), Depth::Flat);
2354 }
2355
2356 #[test]
2357 fn a_badge_carries_a_tone_and_neutral_is_the_bare_class() {
2358 let css = token_rules(&Emit::default());
2359 // Neutral is the absence of a status, not a status named "none".
2360 assert!(css.contains(".badge {\n color: var(--content-muted);"));
2361 assert!(!css.contains("data-tone=\"content-muted\""));
2362 for tone in ["info", "success", "warning", "danger"] {
2363 assert!(
2364 css.contains(&format!(".badge[data-tone=\"{tone}\"]")),
2365 "missing tone {tone}"
2366 );
2367 assert!(css.contains(&format!("color: var(--{tone})")));
2368 }
2369 }
2370
2371 #[test]
2372 fn a_chip_is_raised_and_latches_into_a_well() {
2373 let css = token_rules(&Emit::default());
2374 assert!(css.contains(".chip {"));
2375 assert!(css.contains(".chip.latched {"));
2376 assert!(css.contains(".chip:active {"));
2377 // The whole difference from a badge: it answers a click.
2378 assert!(Token::Chip { removable: false }.interactive());
2379 assert!(!Token::Badge.interactive());
2380 }
2381
2382 #[test]
2383 fn only_a_tab_comes_forward_when_chosen() {
2384 // The folder semantic. Collapsing the three selectors would lose it.
2385 let css = selector_rules(&Emit::default());
2386 assert!(css.contains(".tab.chosen {"));
2387 assert!(css.contains(".segment.chosen {"));
2388 assert!(css.contains(".toggle.chosen {"));
2389 assert_eq!(Selector::Tabs.chosen(), Depth::Raised);
2390 assert_eq!(Selector::Segmented.chosen(), Depth::Well);
2391 assert_eq!(Selector::Toggle.chosen(), Depth::Well);
2392
2393 let tab = css
2394 .lines()
2395 .skip_while(|l| !l.starts_with(".tab.chosen {"))
2396 .take_while(|l| !l.starts_with('}'))
2397 .collect::<Vec<_>>()
2398 .join("\n");
2399 assert!(
2400 tab.contains("var(--bevel-raised)"),
2401 "tab was held in: {tab}"
2402 );
2403 }
2404
2405 #[test]
2406 fn an_unchosen_tab_recedes_without_looking_picked() {
2407 let css = selector_rules(&Emit::default());
2408 // Recessed by colour and given no edge. An edge would make every option
2409 // look picked; flat would leave the chosen one nothing to come forward
2410 // from, which is the gap makeover-layout 0.3.0 closed.
2411 assert!(
2412 css.contains(".tab {\n background: var(--surface-sunken);\n}"),
2413 "unchosen tab is not recessed: {css}"
2414 );
2415 assert_eq!(Selector::Tabs.unchosen(), Depth::Sunken);
2416 assert!(css.contains(".tab:hover {"));
2417 }
2418
2419 #[test]
2420 fn a_segment_stands_up_so_the_chosen_one_can_be_held_in() {
2421 // The inverse of the tab, and why the three selectors are not one
2422 // member with a flag.
2423 let css = selector_rules(&Emit::default());
2424 assert!(css.contains(".segment {\n background: var(--surface-raised);"));
2425 assert_eq!(Selector::Segmented.unchosen(), Depth::Raised);
2426 assert_eq!(Selector::Segmented.chosen(), Depth::Well);
2427 }
2428
2429 #[test]
2430 fn a_rows_actions_are_shown_at_rest() {
2431 let css = row_rules(&Emit::default());
2432
2433 // The hover reveal is gone, and with it every escape it needed. What
2434 // it hid was hidden from pointer users alone, who are the ones
2435 // scanning a list to learn what can be done to a row.
2436 assert!(!css.contains("opacity"), "{css}");
2437 assert!(!css.contains("pointer-events"), "{css}");
2438 assert!(!css.contains(":hover"), "{css}");
2439 assert!(!css.contains(":focus-within"), "{css}");
2440
2441 // Nor is it hidden any other way. `display: none` would reflow the row
2442 // and `visibility: hidden` would take the actions out of the focus
2443 // order; the point is that neither is reached for.
2444 assert!(!css.contains("display: none"), "{css}");
2445 assert!(!css.contains("visibility:"), "{css}");
2446 }
2447
2448 #[test]
2449 fn a_figures_tone_lands_on_the_delta_when_there_is_one() {
2450 // 0.13.0. The delta is the part that reads as good or bad; the number
2451 // itself is an ordinary fact. A figure with no delta has nowhere else to
2452 // put the colour, so the value takes it, and `:has` is what lets one
2453 // attribute mean both without the emitter choosing an element.
2454 let css = stylesheet(&Emit::default());
2455
2456 assert!(
2457 css.contains(".figure[data-tone=\"success\"] > .figure-change"),
2458 "{css}"
2459 );
2460 assert!(
2461 css.contains(
2462 ".figure[data-tone=\"success\"]:not(:has(> .figure-change)) > .figure-value"
2463 ),
2464 "{css}"
2465 );
2466 // The caption is the noun and never takes the tone.
2467 assert!(
2468 !css.contains("[data-tone=\"success\"] > .figure-caption"),
2469 "{css}"
2470 );
2471 }
2472
2473 #[test]
2474 fn the_three_text_parts_take_their_intents_and_actions_inherits() {
2475 let css = row_rules(&Emit::default());
2476 assert!(css.contains(".row-primary {\n color: var(--content);"));
2477 assert!(css.contains(".row-secondary {\n color: var(--content-secondary);"));
2478 assert!(css.contains(".row-meta {\n color: var(--content-muted);"));
2479 // Actions carry controls, not text. Pinning the colour it would inherit
2480 // anyway is louder than saying nothing.
2481 assert!(!css.contains(".row-actions {\n color:"));
2482 }
2483
2484 #[test]
2485 fn the_token_strip_takes_no_colour_of_its_own() {
2486 // makeover-layout 0.9.0. A token carries its own tone, so a colour on
2487 // the strip would be a rule fighting the things sitting in it -- the
2488 // same reasoning as actions, reached for a different reason.
2489 let css = row_rules(&Emit::default());
2490 assert!(!css.contains(".row-tokens {\n color:"));
2491 }
2492
2493 #[test]
2494 fn an_unknown_row_part_renders_plainly_rather_than_failing_to_build() {
2495 // What `#[non_exhaustive]` bought and what it cost. `part_class` can no
2496 // longer be exhaustive, so a member added upstream lands as a bare
2497 // class with no rule instead of stopping the build. Asserting the
2498 // fallback exists is what keeps it from being written as `unreachable!`
2499 // by someone who reads the match as closed.
2500 assert_eq!(part_class(RowPart::Tokens), "row-tokens");
2501 assert_eq!(part_class(RowPart::Meta), "row-meta");
2502 }
2503
2504 #[test]
2505 fn a_link_takes_the_action_colour_the_theme_actually_defines() {
2506 // `--action-primary` shipped here for months and no theme has ever
2507 // defined it, so every `.link` dropped its colour declaration outright
2508 // and fell back to inherited text. Nothing caught it because the sheet
2509 // is valid CSS either way; MNW's no-undefined-token lint is what found
2510 // it, 2026-08-14. The hover arm two lines below was always `--action-hover`,
2511 // which is what makes the typo legible in hindsight.
2512 let css = link_rules(&Emit::default());
2513 assert!(css.contains("color: var(--action);"));
2514 assert!(!css.contains("--action-primary"));
2515 assert!(css.contains("color: var(--action-hover);"));
2516 }
2517
2518 #[test]
2519 fn the_progress_trough_is_a_well() {
2520 let css = progress_rules(&Emit::default());
2521 assert!(css.contains(".progress {"));
2522 assert!(css.contains("box-shadow: var(--bevel-inset)"));
2523 assert!(css.contains(".progress > .progress-fill {"));
2524 assert!(css.contains("background: var(--action)"));
2525 // A bare `.fill` would catch things that have nothing to do with
2526 // progress once the sheet lands unprefixed.
2527 assert!(!css.contains("> .fill "));
2528 }
2529
2530 #[test]
2531 fn a_progress_bar_can_carry_a_tone_and_defaults_to_action() {
2532 let css = progress_rules(&Emit::default());
2533 // Untoned is --action, not Tone::Neutral's content-muted: a bar with no
2534 // status is still reporting progress, and muted would read as disabled.
2535 assert!(css.contains(".progress > .progress-fill {\n background: var(--action);"));
2536 assert!(!css.contains("progress-fill {\n color: var(--content-muted)"));
2537 for tone in ["info", "success", "warning", "danger"] {
2538 assert!(
2539 css.contains(&format!(".progress > .progress-fill[data-tone=\"{tone}\"]")),
2540 "missing progress tone {tone}"
2541 );
2542 }
2543 // goingson's two live cases, which is why the tones are emitted at all.
2544 assert!(css.contains("[data-tone=\"success\"] {\n background: var(--success);"));
2545 assert!(css.contains("[data-tone=\"danger\"] {\n background: var(--danger);"));
2546 }
2547
2548 #[test]
2549 fn no_scrollbar_track_is_emitted() {
2550 // Decision 3's negative half. It was on the phase A list and came off;
2551 // this is what stops it drifting back in.
2552 let css = stylesheet(&Emit::default());
2553 assert!(!css.contains("scrollbar"));
2554 assert!(!css.contains("::-webkit"));
2555 }
2556
2557 #[test]
2558 fn an_invalid_field_is_ringed_without_being_lit() {
2559 let css = surface_rules(&Emit::default());
2560 assert!(css.contains(".field {"));
2561 // The ARIA attribute, not a class: one fact, read by both the visual
2562 // and the accessible state, so they cannot drift.
2563 assert!(css.contains(".field[aria-invalid=\"true\"] {"));
2564 assert!(!css.contains(".field.invalid"));
2565 // A flat ring: this edge says "wrong", and a two-tone bevel would have
2566 // it say "raised" at the same time.
2567 assert!(css.contains("0 0 0 1px var(--danger)"));
2568 }
2569
2570 #[test]
2571 fn an_invalid_field_keeps_the_well_underneath_it() {
2572 // box-shadow is not additive. A lone ring replaces the bevel and drops
2573 // the well out from under the field, which is what this emitted before
2574 // 0.5.0 and is the whole reason the rule composes.
2575 let css = surface_rules(&Emit::default());
2576 let invalid = css
2577 .lines()
2578 .skip_while(|l| !l.starts_with(".field[aria-invalid"))
2579 .take_while(|l| !l.starts_with('}'))
2580 .collect::<Vec<_>>()
2581 .join("\n");
2582 assert!(
2583 invalid.contains("var(--bevel-inset)"),
2584 "the well was dropped: {invalid}"
2585 );
2586 assert!(invalid.contains("var(--danger)"));
2587 }
2588
2589 #[test]
2590 fn button_and_card_come_out_identical_by_construction() {
2591 // The duplication phase A deletes. They are the same composition, so
2592 // the only honest way to emit both is from one call.
2593 let opts = Emit::default();
2594 let css = surface_rules(&opts);
2595 assert_eq!(
2596 depth_declarations(Depth::Raised),
2597 depth_declarations(Depth::Raised)
2598 );
2599 assert!(css.contains(".button {"));
2600 assert!(css.contains(".card {"));
2601 assert_eq!(
2602 interactive_rules("button", Depth::Raised, &Emit::default()).replace("button", "card"),
2603 interactive_rules("card", Depth::Raised, &Emit::default())
2604 );
2605 }
2606
2607 #[test]
2608 fn a_prefix_reaches_the_component_classes_too() {
2609 let opts = Emit {
2610 class_prefix: "mo-",
2611 ..Emit::default()
2612 };
2613 let css = stylesheet(&opts);
2614 for name in [
2615 "mo-button",
2616 "mo-card",
2617 "mo-field",
2618 "mo-badge",
2619 "mo-chip",
2620 "mo-tab",
2621 "mo-row-primary",
2622 "mo-progress",
2623 "mo-progress-fill",
2624 ] {
2625 assert!(css.contains(&format!(".{name}")), "unprefixed: {name}");
2626 }
2627 // The bare names must be gone entirely, or a prefixed build still
2628 // collides with the app's own stylesheet.
2629 assert!(!css.contains(".button {"));
2630 assert!(!css.contains(".card {"));
2631 assert!(!css.contains(".badge {"));
2632 }
2633
2634 #[test]
2635 fn the_class_a_renderer_puts_on_an_option_is_the_one_the_rules_key_off() {
2636 // `option_class` is the contract a screen renderer writes markup
2637 // against, and the rules below are the other half of it. They come off
2638 // one mapping now, so this asserts the mapping is the one that reaches
2639 // the stylesheet rather than that two lists still agree.
2640 let css = stylesheet(&Emit::default());
2641 for selector in [Selector::Tabs, Selector::Segmented, Selector::Toggle] {
2642 let name = option_class(selector);
2643 assert!(css.contains(&format!(".{name} {{")), "{name}: {css}");
2644 assert!(css.contains(&format!(".{name}.chosen {{")), "{name}: {css}");
2645 }
2646 assert_eq!(option_class(Selector::Tabs), "tab");
2647 }
2648
2649 #[test]
2650 fn the_caret_brings_its_own_gap_and_is_the_glyph_the_description_names() {
2651 let css = stylesheet(&Emit::default());
2652
2653 // The space is inside the glyph, which is what the other two renderers
2654 // write. Emitted bare, every consumer has to add it back, and the
2655 // obvious way to add it -- `content` in an app stylesheet, which is
2656 // unlayered and so outranks this sheet -- deletes the caret instead.
2657 assert!(css.contains("content: \" \\25B2\";"), "{css}");
2658 assert!(css.contains("content: \" \\25BC\";"), "{css}");
2659 assert!(!css.contains("content: \"\\2"), "{css}");
2660
2661 // The arrows this renderer used to draw alone are gone. Composition
2662 // rather than agreement: the glyph comes from `Sort::glyph`, so a
2663 // fourth spelling cannot appear here without appearing everywhere.
2664 assert!(!css.contains("2191") && !css.contains("2193"), "{css}");
2665 assert!(css.contains(&css_escape(Sort::Ascending.glyph())), "{css}");
2666
2667 // Three states, three tones. An idle sortable heading draws its caret
2668 // now rather than reserving a hidden box for it, so there is no
2669 // visibility to order and no reflow left to guard against; what
2670 // separates the states is the colour, and the sorted arms come after
2671 // the idle one because the specificity is the same.
2672 let idle = css
2673 .find(".table-heading[data-sortable]::after")
2674 .expect("the idle caret is emitted");
2675 let sorted = css
2676 .find(".table-heading[aria-sort=\"ascending\"]::after")
2677 .expect("the ascending caret is emitted");
2678 assert!(idle < sorted, "{css}");
2679 assert!(
2680 css[idle..sorted].contains("color: var(--content-secondary);"),
2681 "{css}"
2682 );
2683 assert!(css[sorted..].contains("color: var(--content);"), "{css}");
2684 assert!(!css.contains("visibility: hidden;"), "{css}");
2685 }
2686
2687 #[test]
2688 fn a_destructive_button_has_somewhere_for_its_tone_to_land() {
2689 let css = component_rules(&Emit::default());
2690
2691 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
2692 assert!(
2693 css.contains(&format!(".button[data-tone=\"{}\"]", tone.token())),
2694 "{css}"
2695 );
2696 }
2697 // Colour, not a fill. A red surface is an app's decision about emphasis.
2698 assert!(!css.contains(".button[data-tone=\"danger\"] {\n background"));
2699 }
2700
2701 #[test]
2702 fn a_described_list_is_not_a_bulleted_list() {
2703 let css = component_rules(&Emit::default());
2704 assert!(css.contains(".list {\n list-style: none;"), "{css}");
2705 }
2706
2707 #[test]
2708 fn a_table_lays_itself_out_without_being_told_its_columns() {
2709 // The whole point of the CSS table. A described table's columns are
2710 // known at render time, so anything the stylesheet has to be told about
2711 // them would have to travel with the markup.
2712 let css = component_rules(&Emit::default());
2713
2714 assert!(css.contains(".table {\n display: table;"), "{css}");
2715 assert!(css.contains("display: table-row;"), "{css}");
2716 assert!(css.contains("display: table-cell;"), "{css}");
2717 assert!(!css.contains("grid-template-columns"), "{css}");
2718 }
2719
2720 #[test]
2721 fn a_control_in_a_cell_is_not_painted_as_text() {
2722 // The point of makeover-layout 0.14.0's CellPart, and the table-side
2723 // twin of `the_three_text_parts_take_their_intents_and_actions_inherits`
2724 // above. One `.cell` and one content colour meant a button in a cell
2725 // inherited it.
2726 let css = table_rules(&Emit::default());
2727
2728 assert!(
2729 css.contains(".cell-value {\n color: var(--content);"),
2730 "{css}"
2731 );
2732 assert!(!css.contains(".cell-actions {\n color:"), "{css}");
2733 assert!(!css.contains(".cell-tokens {\n color:"), "{css}");
2734 assert!(!css.contains(".cell-link {\n color:"), "{css}");
2735
2736 // The colour is on the part that is text, never on the container. On
2737 // `.cell` it would cascade into the three parts that are not text,
2738 // which is the bug written as one rule.
2739 assert!(!css.contains(".cell {\n color:"), "{css}");
2740 }
2741
2742 #[test]
2743 fn an_unknown_cell_part_renders_plainly_rather_than_failing_to_build() {
2744 // `part_class`'s obligation, taken on for the table side too. CellPart
2745 // is `#[non_exhaustive]`, so a member added upstream must land as a
2746 // bare class rather than as a build that stops.
2747 assert_eq!(cell_part_class(CellPart::Value), "cell-value");
2748 assert_eq!(cell_part_class(CellPart::Actions), "cell-actions");
2749 }
2750
2751 #[test]
2752 fn a_column_drops_by_its_priority_and_never_by_its_position() {
2753 let css = component_rules(&Emit::default());
2754
2755 // Optional goes at the narrowest class and secondary goes with it,
2756 // which is `kept_at`'s cutoff walk said as two queries.
2757 let compact = css
2758 .find(&format!("@media {}", SizeClass::Compact.media_condition()))
2759 .expect("a compact query");
2760 let medium = css
2761 .find(&format!("@media {}", SizeClass::Medium.media_condition()))
2762 .expect("a medium query");
2763 assert!(css[compact..].contains(".cell-drops-next"), "{css}");
2764 assert!(!css[medium..].contains(".cell-drops-next"), "{css}");
2765
2766 // Essential columns are never mentioned, because not being mentioned is
2767 // already what never dropping means.
2768 assert!(!css.contains(".cell-keeps"), "{css}");
2769
2770 // And nothing counts. `nth-child` is the bug the priority vocabulary
2771 // exists to end.
2772 assert!(!css.contains("nth-child"), "{css}");
2773 }
2774
2775 #[test]
2776 fn a_track_places_by_custom_property_and_never_by_a_size() {
2777 let css = track_rules(&Emit::default());
2778
2779 // Placement arrives from the caller, computed once by Track::fraction.
2780 // If either of these becomes a literal, three renderers have started
2781 // disagreeing about where 09:30 is.
2782 assert!(css.contains("top: var(--track-at"), "{css}");
2783 assert!(css.contains("height: var(--track-for"), "{css}");
2784
2785 // Overlap lanes default so an entry naming neither is full width.
2786 assert!(css.contains("--track-lane, 0"), "{css}");
2787 assert!(css.contains("--track-lanes, 1"), "{css}");
2788
2789 // The refusal that matters. A slot height here would be this crate
2790 // deciding how tall a quarter of an hour is, which is the thing
2791 // makeover-geometry owns and the reason `.track` gets no height at all.
2792 assert!(!css.contains("height: var(--track-slot"), "{css}");
2793 for size in ["px", "rem", "em", "vh"] {
2794 let bare = css
2795 .lines()
2796 .filter(|l| !l.contains("var(--"))
2797 .any(|l| l.contains(size));
2798 assert!(!bare, "track_rules named a {size} outside a var(): {css}");
2799 }
2800 }
2801
2802 #[test]
2803 fn a_relaxed_part_clamps_and_a_tight_one_says_nothing() {
2804 let css = stylesheet(&Emit::default());
2805 assert!(css.contains(".row-relaxed {"));
2806 assert!(css.contains("-webkit-line-clamp: 2;"));
2807 // The count is `Flow`'s, not this crate's. If the tier ever means three
2808 // lines, this fails here rather than in an app.
2809 assert!(css.contains(&format!("line-clamp: {};", Flow::Relaxed.lines())));
2810 // Tight gets no rule at all: one line is what a run already does, and a
2811 // class per part saying so is a declaration that changes nothing.
2812 assert!(!css.contains("row-tight"));
2813 assert_eq!(crate::list::flow_class(Flow::Relaxed), Some("row-relaxed"));
2814 assert_eq!(crate::list::flow_class(Flow::Tight), None);
2815 // Emitted, therefore checkable: an app's dead-vocabulary seal and the
2816 // overlap check both read `vocabulary::names`, so a class the renderer
2817 // can write and that list does not carry is invisible to both.
2818 assert!(crate::vocabulary::names(&Emit::default()).contains("row-relaxed"));
2819 }
2820
2821 #[test]
2822 fn the_two_kinds_of_wait_stop_rendering_identically() {
2823 // The state `d43ea1c5` fixes: the emitter had been writing
2824 // `data-awaiting` for months and nothing styled either value, so a
2825 // measured wait and an unmeasured one drew the same nothing.
2826 let css = stylesheet(&Emit::default());
2827 assert!(css.contains("[data-awaiting]::after"), "{css}");
2828 assert!(
2829 css.contains("[data-awaiting][aria-busy=\"true\"]::after"),
2830 "the mark is drawn only while something is actually waiting"
2831 );
2832 assert!(
2833 css.contains("[data-awaiting=\"determinate\"][aria-busy=\"true\"]::after"),
2834 "the measured half is its own drawing"
2835 );
2836 }
2837
2838 #[test]
2839 fn the_blink_takes_its_cadence_and_never_names_one() {
2840 // Three renderers draw this mark. A number written here would be a
2841 // second heartbeat for one wait.
2842 let css = stylesheet(&Emit::default());
2843 assert!(
2844 css.contains("calc(var(--cadence-activity) * 2)"),
2845 "a half-period doubled, not a literal"
2846 );
2847 assert!(!css.contains("500ms"), "{css}");
2848 }
2849
2850 #[test]
2851 fn a_bar_nobody_is_counting_is_empty_rather_than_full() {
2852 // Rule 1. The share defaults to zero, so a determinate control with no
2853 // binder watching bytes draws a trough. A default of 1 would be the
2854 // confidently-wrong drawing the rule exists to forbid.
2855 let css = stylesheet(&Emit::default());
2856 assert!(css.contains("var(--awaiting-share, 0)"), "{css}");
2857 }
2858
2859 #[test]
2860 fn motion_off_leaves_the_mark_lit_because_the_keyframes_do_the_dimming() {
2861 // `makeover_timing::reduced_motion_css` sets `--cadence-activity: 0ms`,
2862 // and a zero-length animation leaves the element in its base style
2863 // rather than at its last keyframe. So the base has to be the lit one.
2864 // The inverted spelling would blank the mark for a reader who asked for
2865 // less motion, which answers a request nobody made.
2866 let css = stylesheet(&Emit::default());
2867 let busy = css
2868 .split("[data-awaiting][aria-busy=\"true\"]::after {")
2869 .nth(1)
2870 .expect("the busy rule");
2871 let busy = busy.split('}').next().expect("its body");
2872 assert!(
2873 busy.contains("background: var(--action);"),
2874 "the base state is lit: {busy}"
2875 );
2876 }
2877
2878 #[test]
2879 fn the_whole_sheet_still_names_every_colour() {
2880 // The crate's founding property, asserted over the component layer and
2881 // not only the primitives.
2882 let css = stylesheet(&Emit::default());
2883 assert!(!css.contains('#'));
2884 assert!(!css.contains("rgb"));
2885 for line in css.lines() {
2886 // Declarations only: a selector or an at-rule can carry a colon of
2887 // its own (`:root`, `:hover`, `@media (hover: hover)`) and declares
2888 // nothing. Keyed on the trailing semicolon rather than on leading
2889 // indentation, which only ever worked as a proxy for nesting depth
2890 // and stopped when the sheet gained a cascade layer around it.
2891 let trimmed = line.trim();
2892 if !trimmed.ends_with(';') {
2893 continue;
2894 }
2895 let Some((_, value)) = trimmed.split_once(": ") else {
2896 continue;
2897 };
2898 if value.contains("var(--") {
2899 continue;
2900 }
2901 // Everything left has to be a keyword, a number or a
2902 // caller-supplied length, never a colour.
2903 //
2904 // The length arm is what the comment above always claimed and the
2905 // list never covered: `border_width` arrives from `Emit` and lands
2906 // bare in the focus ring's offset, where the bevel had only ever
2907 // used it inside an `inset` shadow.
2908 let opts = Emit::default();
2909 assert!(
2910 value.contains("inset")
2911 || value.contains(opts.border_width)
2912 || value.contains(opts.focus_width)
2913 // 0.12.0's two: a sortable header is a control and says so
2914 // with the pointer, and the caret is this renderer's own
2915 // expression of `aria-sort`. Neither is a colour, which is
2916 // what this test is actually about, and neither is a size,
2917 // which is the other thing this crate must not name. The
2918 // leading space inside the glyph is the same thing the other
2919 // two renderers write into theirs, so it is part of the
2920 // caret rather than spacing this crate decided on.
2921 || value
2922 .trim_start_matches('"')
2923 .trim_start()
2924 .starts_with("\\2")
2925 || matches!(
2926 value.trim_end_matches(';'),
2927 "0" | "1"
2928 // The wait's mark and bar, 0.60.0. An empty
2929 // `content` is what brings a pseudo-element into
2930 // existence with nothing in it, and `step-end`
2931 // is an easing: the blink is two states, not a
2932 // slide between them. Neither is a colour, and
2933 // neither is a magnitude.
2934 | "\"\""
2935 // Where the mark sits on the line it joins.
2936 // Alignment is structure, the same way `display`
2937 // is, and `baseline` is the initial value said out
2938 // loud so a host stylesheet cannot leave it
2939 // wherever an earlier rule put it.
2940 | "baseline"
2941 | "inline-block"
2942 | "none"
2943 | "auto"
2944 | "not-allowed"
2945 | "pointer"
2946 // The caret's reserved box. Visibility is presence,
2947 // not magnitude and not colour.
2948 | "hidden"
2949 | "visible"
2950 // The link's two signals. `underline` is a line and
2951 // `inherit` defers to whatever the app set, so
2952 // neither names a colour or a magnitude.
2953 | "underline"
2954 | "inherit"
2955 // The table frame. `display` is structure and not a
2956 // size; `nowrap` is what makes a content column
2957 // content. The two widths are the awkward pair and
2958 // they are still not sizes: `100%` is "all of
2959 // whatever you were given" and `1%` is the CSS
2960 // table idiom for "shrink to fit", which is a
2961 // behaviour spelled as a number because CSS has no
2962 // keyword for it. Neither names a magnitude, which
2963 // is the thing this crate leaves to
2964 // makeover-geometry.
2965 | "table"
2966 | "table-row"
2967 | "table-cell"
2968 | "nowrap"
2969 | "100%"
2970 | "1%"
2971 // The time axis, 0.42.0. `position` is the one
2972 // property whose whole job is where a thing sits,
2973 // which is exactly what this crate spent its life
2974 // refusing to say -- so it is worth being exact
2975 // about why these two are not that refusal
2976 // breaking.
2977 //
2978 // Neither names a magnitude. `relative` says the
2979 // track is what its entries resolve against, and
2980 // `absolute` says an entry is placed rather than
2981 // flowed. *Where* each entry lands is
2982 // `--track-at` and `--track-for`, custom
2983 // properties the caller sets from
2984 // `Track::fraction`, and they are skipped by the
2985 // `var(--` arm above like every other value this
2986 // crate refuses to decide.
2987 //
2988 // The rule that would break the refusal is a slot
2989 // height, and there is none: the track's height is
2990 // the app's, so the percentages have something to
2991 // resolve against and this crate still never says
2992 // how tall a day is.
2993 | "relative"
2994 | "absolute"
2995 // A run's five, 0.49.0. `flex`, `wrap` and
2996 // `center` are structure and alignment, the same
2997 // reading `table` gets: which way members are laid
2998 // out and how they line up, never how much of
2999 // anything.
3000 //
3001 // The two intrinsic keywords are the interesting
3002 // pair and they are the opposite of a size. A
3003 // magnitude is a number somebody chose;
3004 // `min-content` and `max-content` are the browser
3005 // being asked what the members themselves come to,
3006 // which is the derived minimum the room ruling
3007 // requires and the reason no breakpoint appears
3008 // anywhere in these rules. `1 1 max-content` is
3009 // grow, shrink and that basis, so its two digits
3010 // are ratios rather than lengths.
3011 | "flex"
3012 | "wrap"
3013 | "center"
3014 | "min-content"
3015 | "1 1 max-content"
3016 // A picture's three, 0.36.0. `block` is structure
3017 // for the reason `table` is: an inline image sits
3018 // on the baseline and carries a descender's worth
3019 // of space under it, which is a fact about
3020 // replaced elements rather than a size this crate
3021 // chose. `cover` and `contain` are `Fit`'s two
3022 // named members reaching CSS unchanged, which is
3023 // an intent arriving rather than a value being
3024 // picked.
3025 | "block"
3026 | "cover"
3027 | "contain"
3028 // A relaxed part's three, and the third is the
3029 // awkward one. `-webkit-box` and `vertical` are
3030 // structure: they say the part is a box of lines
3031 // stacked downward, which is the only way CSS lets
3032 // anyone ask for a clamp at all.
3033 //
3034 // `2` is a count of lines, not a length. The
3035 // distinction this crate holds is between naming a
3036 // magnitude -- a padding, a height, a font size,
3037 // all of which belong to makeover-geometry -- and
3038 // naming how many of something there are. A line's
3039 // height is still the app's, so two lines is
3040 // whatever two of the app's lines come to, and
3041 // nothing here decides how tall that is. It is also
3042 // not a value picked here: it is `Flow::Relaxed`'s
3043 // own answer arriving unchanged, the same way
3044 // `cover` and `contain` are `Fit`'s.
3045 | "-webkit-box"
3046 | "vertical"
3047 | "2"
3048 ),
3049 "unrecognised literal value: {line}"
3050 );
3051 }
3052 }
3053
3054 #[test]
3055 fn flat_emits_nothing_at_all() {
3056 assert_eq!(depth_class(Depth::Flat, &Emit::default()), None);
3057 assert!(!depth_rules(&Emit::default()).contains("flat"));
3058 }
3059
3060 #[test]
3061 fn a_prefix_namespaces_every_class() {
3062 let opts = Emit {
3063 class_prefix: "mo-",
3064 ..Emit::default()
3065 };
3066 let css = depth_rules(&opts);
3067 assert!(css.contains(".mo-raised {"));
3068 assert!(css.contains(".mo-well {"));
3069 assert!(!css.contains(".raised {"));
3070 }
3071
3072 #[test]
3073 fn the_border_width_is_the_callers() {
3074 let opts = Emit {
3075 border_width: "2px",
3076 ..Emit::default()
3077 };
3078 assert!(bevel_shadow(Bevel::Raised, &opts).contains("inset 2px 2px 0"));
3079 }
3080
3081 #[test]
3082 fn edges_agree_with_the_description() {
3083 // Not a tautology: it is the guard that a CSS-shaped convenience never
3084 // quietly reverses which side is lit.
3085 let (tl, br) = Bevel::Raised.edges();
3086 assert_eq!(tl.token(), Edge::Light.token());
3087 assert_eq!(br.token(), Edge::Dark.token());
3088 }
3089 }
3090