/*
 * Everything that is not a colour or a size.
 *
 * Two files, the same split the app uses: tokens.css holds the palette and
 * the scale, this holds layout. CSS is global, so a third file would create
 * a boundary the language does not enforce, and the one thing it reliably
 * buys is writing a rule that already exists somewhere you did not look.
 *
 * tokens.css is a copy from the app and is not edited. This file is ours.
 */

/* --- this page's own variables -----------------------------------------
 * Not colours and not the type scale, so these do not belong in tokens.css
 * and copying that file from the app will never touch them.
 *
 * The easing curves are the point. CSS's built-in `ease-out` is weak enough
 * that a 200ms transition using it reads as a slow 300ms one; a stronger
 * curve moves early, which is the part of the motion a person actually
 * watches. These two are the standard strong variants.
 */

:root {
  --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
  --ease-in-out: cubic-bezier(0.77, 0, 0.175, 1);
}

/* --- reset, the small amount of it that earns its place --------------- */

*,
*::before,
*::after {
  box-sizing: border-box;
}

/* The page ends in a band with its own background. Without this the body's
 * --bg shows below the last one as a stripe of a different colour, which is
 * what it was doing. */
html {
  background: var(--surface-sunken);
  /* Without this, jumping to #download puts the section heading underneath
   * the sticky header. Slightly more than the header's own height. */
  scroll-padding-top: 5rem;
}

/* Smooth only for people who have not asked for less motion — the blanket
 * reduced-motion rule further down sets it back to auto. */
@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  /* 1.6 rather than a tighter figure: this page is read, not scanned. */
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
}

/* A heading is serif unless it says otherwise. Same rule as the app, and the
 * same trap: a new small heading that sets only size and weight comes out as
 * a serif heading at the wrong weight. Set the family when you mean sans. */
h1,
h2,
h3 {
  font-family: var(--font-display);
  font-weight: 500;
  line-height: 1.15;
  margin: 0;
  /* Serif at display sizes sets loose by default. */
  letter-spacing: -0.015em;
  text-wrap: balance;
}

p {
  margin: 0;
  text-wrap: pretty;
}

/* --- layout ------------------------------------------------------------
 * A band is a full-width horizontal stripe; a wrap is the readable column
 * inside it. Splitting them is what lets a section's background run edge to
 * edge while its text stays measured.
 */

.band {
  /* The side padding lives here, once, so no inner element has to remember
   * it and no viewport can lose it. */
  padding-inline: clamp(1.25rem, 5vw, 3rem);
  padding-block: clamp(3.5rem, 7vw, 5.5rem);
}

.band--sunken {
  background: var(--surface-sunken);
}

.wrap {
  /* 68rem is wide enough for two columns and narrow enough that a single
   * column of prose inside it never runs past a comfortable measure. */
  max-width: 68rem;
  margin-inline: auto;
}

/* Prose sits narrower than the wrap it is in. A line of body text past about
 * 70 characters loses the reader on the return sweep. */
.prose {
  max-width: 34rem;
}

/* --- motion ------------------------------------------------------------
 * Reduced motion means fewer and gentler animations, not none: opacity and
 * colour changes aid comprehension and stay. What goes is movement — the
 * transforms and the scroll-driven rise.
 */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-property: opacity, background-color, color, border-color !important;
    scroll-behavior: auto !important;
  }
}

/* --- the bars top and bottom -------------------------------------------
 * One class, two very different jobs. The footer uses it too, so everything
 * sticky below is scoped to .topbar--head — a `position: sticky` on the bare
 * class would pin the footer to the bottom of the viewport as well.
 */

.topbar {
  padding-inline: clamp(1.25rem, 5vw, 3rem);
  padding-block: 1.1rem;
}

.topbar--head {
  position: sticky;
  top: 0;
  /* Above the page, below nothing else — there are no other layers. */
  z-index: 10;
  /* The resting state, and the state Firefox keeps: translucent rather than
   * clear. 90% is high enough that the text contrast measured against --bg
   * still holds, because whatever scrolls underneath only contributes a tenth
   * of the colour — and every surface on this page (--bg, --surface-sunken,
   * --surface) sits within a few percent of the others in lightness, so that
   * tenth cannot move it far. A lower opacity would look better and would put
   * the header text on an unmeasurable background. */
  background: color-mix(in srgb, var(--bg) 90%, transparent);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

/* At rest the header is fully transparent, so it reads as the top of the page
 * rather than a bar drawn across it — no wash, no line. It settles into the
 * resting state above within the first 96px of scroll, by which point content
 * is passing underneath and needs separating from the text on top.
 *
 * `scroll()` rather than `view()` — progress is the document's scroll
 * position, not this element's trip through the viewport, and a sticky
 * element never takes that trip. Support is the same as the reveal below:
 * Chrome and Edge 115+, Safari 26+, Firefox behind a flag (17 Sep 2026), so
 * a browser without it simply keeps the resting state, which is legible and
 * measured. Nothing depends on the animation.
 *
 * Text contrast is measured against the blend, not against the tokens, which
 * is the only way to catch what a translucent bar actually does. The worst
 * case is not a surface scrolling under it but the h1: 90% --bg over --text
 * gives an effective background of #e6e2dd in light and #2e2a26 in dark, on
 * which the wordmark and link measure 11.29:1 and 11.30:1 and the Windows tag
 * 5.08:1 and 6.15:1. At rest, on plain --bg, they are 13.62:1 and 6.13:1. */
@supports (animation-timeline: scroll()) {
  @media (prefers-reduced-motion: no-preference) {
    .topbar--head {
      animation: topbar-settle linear both;
      animation-timeline: scroll(root block);
      animation-range: 0 96px;
    }
  }
}

@keyframes topbar-settle {
  from {
    background-color: color-mix(in srgb, var(--bg) 0%, transparent);
    border-bottom-color: transparent;
  }
  to {
    background-color: color-mix(in srgb, var(--bg) 90%, transparent);
    border-bottom-color: var(--border);
  }
}

.topbar--foot {
  border-top: 1px solid var(--border);
  background: var(--surface-sunken);
}

.topbar__nav {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.75rem 1.25rem;
}

.topbar__link {
  font-size: 0.875rem;
  /* --text, not --text-detail: this is the only interactive thing in the bar
   * and it should not read as quieter than the label beside it. 13.62:1 on
   * --bg, 12.49:1 on --accent-soft where the hero puts it. */
  color: var(--text);
  text-decoration: none;
  padding: 0.3rem 0.8rem;
  /* --text-detail. Two tokens were wrong before this one, and the second was
   * wrong for an interesting reason.
   *
   * --border-strong measures 1.49:1 against the page; this repo already took
   * a button shape away from the download control over exactly that, so
   * reaching for it again in the one bar that is on screen the whole time
   * would have repeated the mistake.
   *
   * --text-faint looked fine when measured against the surfaces that scroll
   * under the header — 3.40:1 at worst. But the worst thing passing under a
   * sticky header is not a surface, it is *text*. With the h1 beneath it the
   * effective background becomes 90% --bg over --text, and the border falls
   * to 2.84:1 in the light palette: under the floor, and only visible by
   * measuring the blend rather than the tokens.
   *
   * --text-detail against that same blend is 5.08:1 light and 6.15:1 dark
   * (17 Sep 2026), which holds with room to spare and lets the background
   * stay at 90% rather than being pushed opaque to rescue a thin line. */
  border: 1px solid var(--text-detail);
  border-radius: var(--radius-full);
  transition:
    background-color 160ms var(--ease-out),
    border-color 160ms var(--ease-out),
    transform 160ms var(--ease-out);
}

@media (hover: hover) and (pointer: fine) {
  .topbar__link:hover {
    background: var(--surface-hover);
    border-color: var(--accent-line);
  }
}

.topbar__link:active {
  transform: scale(0.97);
}

.row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  align-items: baseline;
  justify-content: space-between;
}

.wordmark {
  font-family: var(--font-display);
  font-size: 1.15rem;
  letter-spacing: -0.01em;
}

.tag,
.muted {
  /* --text-detail, not --text-muted. Muted measures 4.47:1 on --bg and 4.07:1
   * on --surface-sunken (17 Sep 2026) — under the 4.5 floor for text this
   * small, on both surfaces this page uses. Detail clears it at 6.13 and 5.58.
   * The app made the same move for the Sharing rungs, for the same reason. */
  color: var(--text-detail);
  font-size: 0.875rem;
}

/* --- hero ---------------------------------------------------------------
 * Two columns from 62rem up. Before this the whole page was a ~34rem column
 * of text pinned to the left of a 1440px viewport, with the entire right half
 * empty in every section — which was the single worst thing about it.
 *
 * The warm wash fades out by 60%, well above where any text starts, so every
 * measured figure below is still against --bg or --surface.
 */

.band--hero {
  padding-block: clamp(3.5rem, 8vw, 6rem);
  background: linear-gradient(to bottom, var(--accent-soft) 0%, var(--bg) 60%);
}

.hero {
  display: grid;
  gap: clamp(2.5rem, 5vw, 4rem);
  align-items: start;
}

@media (min-width: 62rem) {
  .hero {
    /* Text takes the larger share; the log is a supporting exhibit, not a
     * co-headline. */
    grid-template-columns: 1.15fr 1fr;
    align-items: center;
  }
}

h1 {
  font-size: clamp(2.1rem, 4.6vw, 3.4rem);
  /* 17ch broke this into four short lines with room to spare beside them.
   * 21ch gives three, which is the shape a headline this long wants. */
  max-width: 21ch;
}

.lede {
  margin-top: 1.5rem;
  font-size: 1.125rem;
  color: var(--text-detail);
  max-width: 44ch;
}

/* The limit, said in the open rather than in a footnote. Bordered on the
 * accent line so it reads as deliberate and not as an apology. */
.limit {
  margin-top: 1.5rem;
  padding-left: 1rem;
  border-left: 2px solid var(--accent-line);
  color: var(--text-detail);
  max-width: 40ch;
}

.limit--wide {
  margin-top: 2.5rem;
  max-width: 58ch;
}

.note {
  margin-top: 2rem;
  color: var(--text-detail);
  font-size: 0.875rem;
}

/* --- the card, used by the hero's log ----------------------------------- */

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 1.25rem 1.5rem 1.1rem;
}

.card__title,
.log__title,
.card__foot {
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-detail);
}

.card__foot {
  text-transform: none;
  letter-spacing: 0;
  font-size: 0.8125rem;
  margin-top: 1rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--border);
}

/* --- the hero exhibit ---------------------------------------------------
 * Two halves and a rule between them: what stays, what goes. No amounts, on
 * purpose — see the note in index.html.
 */

.exchange {
  display: grid;
  gap: 0;
}

.exchange__label {
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-detail);
  margin-bottom: 0.75rem;
}

.exchange__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text);
}

/* File names are the thing that does not move, so they are set back a step
 * from the figures that do. */
.exchange__list--files li {
  color: var(--text-detail);
}

/* The dividing line carries the claim, so it is a labelled rule rather than a
 * plain border: a bare line between two lists says they are different, which
 * is not the point being made. */
.exchange__rule {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin: 1.25rem 0;
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-detail);
  white-space: nowrap;
}

.exchange__rule::before,
.exchange__rule::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border);
}

.exchange__foot {
  margin-top: 0.85rem;
  font-size: 0.8125rem;
  color: var(--text-detail);
}

/* --- section headings ---------------------------------------------------
 * The app's answer for naming a group: sans, small, wide-tracked. A heading
 * that set only size and weight would come out serif at the wrong weight.
 */

.section__title {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  /* Same reason as .tag: this is 13px and half of it sits on sunken bands. */
  color: var(--text-detail);
  margin-bottom: 0.75rem;
}

/* The lead sentence under a section title, set larger than body text. Five
 * sections that each opened with the same 16px grey paragraph gave the page
 * no hierarchy below the headline; this is the step between. */
.section__lead {
  font-family: var(--font-display);
  font-size: clamp(1.25rem, 2.2vw, 1.6rem);
  line-height: 1.3;
  letter-spacing: -0.01em;
  max-width: 30ch;
  margin-bottom: 2.5rem;
}

/* --- the demonstration --------------------------------------------------
 * The five levels, shown rather than listed. This replaced a static list of
 * rung names: the name of a level does not tell anyone what it hands over,
 * and the whole argument of the page is what it hands over.
 *
 * The rail is vertical from 52rem up, which is both the app's own shape for
 * the Sharing rungs and the thing that finally gives this section a right
 * half worth having.
 */

.demo {
  display: grid;
  gap: 2rem;
}

/* A grid or flex child defaults to `min-width: auto`, which means it refuses
 * to shrink below the width of its content. The sheet's table is
 * `white-space: nowrap`, so without this a narrow enough viewport would have
 * the column grow to the table's full width and take the page with it.
 *
 * Measured at a 390px viewport (17 Sep 2026): scrollWidth 375, nothing past
 * the edge — so this is hardening against a latent hazard, not a repair of
 * something that was observed breaking. It is set down the chain because each
 * of these is a grid child of the one above it, and any one left at `auto`
 * would be the one that reinstates it. */
.demo,
.demo__stage,
.demo__panels,
.panel,
.sheet {
  min-width: 0;
}

@media (min-width: 52rem) {
  .demo {
    grid-template-columns: 17rem 1fr;
    gap: 3rem;
    align-items: start;
  }
}

.demo__tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

@media (min-width: 52rem) {
  .demo__tabs {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 0.15rem;
  }
}

.demo__tabs button {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  width: 100%;
  text-align: left;
  /* A real <button>, so it is keyboard-reachable and pressable without any
   * of this file's help. The styling strips the native chrome; it does not
   * replace the element with a div wearing a costume. */
  font: inherit;
  font-size: 0.9375rem;
  cursor: pointer;
  padding: 0.6rem 0.85rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  background: none;
  /* --text-detail: 5.58:1 on --surface-sunken, which is the band this sits
   * on (measured 17 Sep 2026). --text-muted would be 4.07 and fail. */
  color: var(--text-detail);
  /* Named properties, never `all`: `all` animates things you did not mean to,
   * including layout properties that cost a frame each. */
  transition:
    background-color 160ms var(--ease-out),
    color 160ms var(--ease-out),
    border-color 160ms var(--ease-out),
    transform 160ms var(--ease-out);
}

/* Gated, because a touch device fires hover on tap and leaves the last-tapped
 * control stuck in its hover state. */
@media (hover: hover) and (pointer: fine) {
  .demo__tabs button:hover {
    background: var(--surface-hover);
    color: var(--text);
  }
}

/* Instant feedback that the interface heard the press. Subtle on purpose —
 * below about 0.95 it reads as the button breaking rather than responding. */
.demo__tabs button:active {
  transform: scale(0.98);
}

.demo__tabs button[aria-selected="true"] {
  background: var(--accent-soft);
  border-color: var(--accent-line);
  color: var(--text);
}

.demo__rung {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-faint);
}

/* --text-detail, not --accent-hover. The accent on --accent-soft measures
 * 4.46:1 (17 Sep 2026) — a hair under the 4.5 floor, and this is 12px mono,
 * which is the size least able to afford it. Detail gives 5.62:1 and still
 * steps up visibly from the --text-faint of an unselected rung. The selected
 * tab is already marked by its wash, its border and its darker label. */
.demo__tabs button[aria-selected="true"] .demo__rung {
  color: var(--text-detail);
}

/* The panels are drawn to look like the app's own sheets, so the page says
 * once, next to the control, that the numbers on them are made up. */
.demo__hint--tight {
  margin-top: 0.6rem;
  padding-top: 0;
  border-top: 0;
}

.demo__hint {
  margin-top: 1.25rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border);
  font-size: 0.8125rem;
  color: var(--text-detail);
}

/* Focus is drawn once, here, for every control on the page. The default ring
 * disappears against a warm background on some browsers. */
.demo__tabs button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--accent-hover);
  outline-offset: 2px;
}

/* Until levels.js runs, every panel is visible and the rail is just a list of
 * labels. .demo--live is what turns it into one-at-a-time. */
.demo__panels {
  display: grid;
  gap: 2.5rem;
}

.demo--live .demo__panels {
  gap: 0;
}

/* The panel swap is a crossfade between two states, so it is a transition and
 * not a keyframe: a transition can be retargeted mid-flight when someone
 * clicks along the rail quickly, where a keyframe restarts from zero.
 *
 * It rises from 4px rather than appearing from nothing, and the blur bridges
 * the moment where both states are briefly legible at once — without it you
 * read two overlapping tables rather than one changing. */
.demo--live .panel {
  transition:
    opacity 180ms var(--ease-out),
    transform 180ms var(--ease-out),
    filter 180ms var(--ease-out);
}

.demo--live .panel[hidden] {
  display: none;
}

.demo--live .panel--entering {
  opacity: 0;
  transform: translateY(4px);
  filter: blur(3px);
}

.panel__head {
  color: var(--text);
  font-size: 1.0625rem;
  margin-bottom: 1rem;
  max-width: 48ch;
}

.panel__note {
  margin-top: 1rem;
  font-size: 0.875rem;
  color: var(--text-detail);
  max-width: 52ch;
}

/* --- the sheet ----------------------------------------------------------
 * A document-ish surface for the figures, matching the app's own. Raised off
 * the sunken band rather than outlined: depth comes from surface and shadow,
 * never from a visible grid of borders.
 */

.sheet {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: 1.1rem 1.4rem;
  overflow-x: auto;
}

.figures {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  /* Tabular figures line the decimal points up without a fixed layout. */
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.figures th {
  text-align: left;
  font-weight: 500;
  font-family: var(--font-sans);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-detail);
  padding-bottom: 0.55rem;
  border-bottom: 1px solid var(--border);
}

.figures td {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}

.figures th + th,
.figures td + td {
  padding-left: 1.5rem;
}

.figures th:last-child,
.figures td:last-child {
  text-align: right;
}

.figures tr:last-child td {
  border-bottom: 0;
}

/* A withheld description is decoration standing in for absence, so
 * --text-faint is the right token and it clears 3:1 on every surface. */
.withheld {
  color: var(--text-faint);
}

.alias {
  color: var(--text-detail);
}

.figures .in {
  /* The app's own token for money arriving, a shade darker than the accent
   * precisely so a figure someone reads clears 4.5:1 on a sheet. */
  color: var(--money-in);
}

.refusal {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--danger);
  padding: 0.4rem 0;
}

/* --- the disclosure log under the demonstration -------------------------
 * Outside the panels, because it is the part that does not change with the
 * level. The refused request is logged exactly like the shared ones.
 */

.log {
  margin-top: 1.75rem;
  padding-top: 1.25rem;
  border-top: 1px dashed var(--border);
}

.log__line {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-detail);
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 0.5rem;
}

.log__time {
  color: var(--text-faint);
}

/* Plain text, not a colour. --money-in on --surface-sunken measures 3.93:1
 * (17 Sep 2026), under the floor for a word someone reads. It is also the
 * better design: colour is reserved for the refusal, so the exceptional line
 * is the one that catches the eye rather than four out of five. */
.log__verb {
  color: var(--text);
}

.log__verb--refused {
  color: var(--danger);
}

/* --- how it works ------------------------------------------------------- */

.steps {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2.5rem;
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
}

.steps li {
  border-top: 1px solid var(--border);
  padding-top: 1.25rem;
}

.steps__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--text-faint);
  margin-bottom: 0.75rem;
}

.steps h3 {
  font-size: 1.35rem;
  margin-bottom: 0.6rem;
}

.steps p {
  color: var(--text-detail);
}

/* --- promises -----------------------------------------------------------
 * Two columns from 52rem up. As a single stack these ran down the left of an
 * otherwise empty band, which made the most important sentences on the page
 * look like small print.
 */

.promises {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.5rem 2.5rem;
  grid-template-columns: repeat(auto-fit, minmax(19rem, 1fr));
}

.promises li {
  padding-left: 1.25rem;
  border-left: 2px solid var(--accent-line);
  color: var(--text-detail);
}

/* --- download ----------------------------------------------------------- */

.download {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem 3rem;
  align-items: center;
  justify-content: space-between;
}

.download__line {
  color: var(--text-detail);
  max-width: 44ch;
}

.button {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 0.5rem;
  font-weight: 500;
  /* --accent-hover, not --accent. White on --accent measures 4.26:1
   * (17 Sep 2026), under the 4.5 floor for text; --accent-hover gives 5.12:1
   * and still clears 3:1 against the page at 4.86:1. The app's own tokens
   * note the same 4.26 figure for the accent as text on a sheet. */
  background: var(--accent-hover);
  color: var(--text-on-accent);
  transition:
    background-color 160ms var(--ease-out),
    transform 160ms var(--ease-out);
}

@media (hover: hover) and (pointer: fine) {
  /* Was a flat #8a5838, which is a darker clay and therefore only correct in
   * the light palette — under dark it made the hovered button recede into the
   * page instead of lifting off it. Mixing toward --text moves it away from
   * the background in whichever direction the theme's background lies. */
  .button:hover {
    background: color-mix(in srgb, var(--accent-hover) 86%, var(--text));
  }
}

.button:active {
  transform: scale(0.97);
}

/* There is nothing to press yet, so this is not shaped like a button.
 * A button-shaped thing that cannot be pressed fails 1.4.11 on its boundary
 * (--border-strong measures 1.49:1 against the page, 17 Sep 2026) and, worse,
 * invites a click that does nothing. It reverts to .button on release day.
 */
.button--inert {
  padding: 0;
  border: 0;
  border-radius: 0;
  background: none;
  transform: none;
  font-weight: 400;
  color: var(--text-detail);
  font-size: 0.875rem;
}

/* --- the reveal ---------------------------------------------------------
 * A scroll-driven fade-and-rise, in CSS, with no library and no scroll
 * listener. `animation-timeline: view()` ties progress to the element's own
 * trip through the viewport, so the browser runs it off the main thread.
 *
 * Checked 17 Sep 2026: Chrome and Edge since 115, Safari since 26, Firefox
 * still behind a flag — MDN lists the property as limited availability, not
 * Baseline. So it is written as pure decoration: the starting opacity lives
 * inside @supports, and a browser without the property never hides anything
 * it cannot then reveal.
 *
 * It is applied to the two lists rather than to everything. Items that all
 * appear at once read as a block dropping in; a short stagger reads as a
 * list arriving. Delays stay under 80ms each — longer and the page feels
 * like it is waiting for itself.
 */

@supports (animation-timeline: view()) {
  @media (prefers-reduced-motion: no-preference) {
    .steps li,
    .promises li,
    .hero__aside .card {
      opacity: 0;
      animation: reveal-rise linear both;
      animation-timeline: view();
      /* Ends inside `entry`, not out in `cover`. An earlier version ran to
       * `cover 22%`, which left items that were already on screen sitting at
       * partial progress — half-faded, with no scrolling left to finish them.
       * Anything half-entered is now fully opaque, and a page shorter than
       * the viewport renders complete rather than permanently dimmed. */
      animation-range: entry 0% entry 50%;
    }

    /* The stagger, such as it is: later items finish later, all still inside
     * entry. 30-80ms is the useful range for a delay; expressed against a
     * scroll timeline it is a few percent, not a duration. */
    .steps li:nth-child(2),
    .promises li:nth-child(2) {
      animation-range: entry 0% entry 62%;
    }

    .steps li:nth-child(3),
    .promises li:nth-child(3) {
      animation-range: entry 0% entry 74%;
    }
  }
}

@keyframes reveal-rise {
  from {
    opacity: 0;
    transform: translateY(0.75rem);
  }
  to {
    opacity: 1;
    transform: none;
  }
}