/*
 * Desktop Material documentation hub — Material Design 3 (M3 Expressive).
 *
 * Self-contained: no web fonts, no CDN, no external requests. Colour, type,
 * shape, elevation and motion all come from the M3 baseline token set below.
 */

/* ---------------------------------------------------------------- tokens */

:root {
  color-scheme: light;

  /* M3 baseline light scheme */
  --md-primary: #6750a4;
  --md-on-primary: #ffffff;
  --md-primary-container: #eaddff;
  --md-on-primary-container: #21005d;
  --md-secondary: #625b71;
  --md-on-secondary: #ffffff;
  --md-secondary-container: #e8def8;
  --md-on-secondary-container: #1d192b;
  --md-tertiary: #7d5260;
  --md-on-tertiary: #ffffff;
  --md-tertiary-container: #ffd8e4;
  --md-on-tertiary-container: #31111d;
  --md-error: #b3261e;
  --md-on-error: #ffffff;
  --md-error-container: #f9dedc;
  --md-on-error-container: #410e0b;
  --md-surface: #fef7ff;
  --md-on-surface: #1d1b20;
  --md-surface-variant: #e7e0ec;
  --md-on-surface-variant: #49454f;
  --md-surface-container-lowest: #ffffff;
  --md-surface-container-low: #f7f2fa;
  --md-surface-container: #f3edf7;
  --md-surface-container-high: #ece6f0;
  --md-surface-container-highest: #e6e0e9;
  --md-outline: #6f6779;
  --md-outline-variant: #cac4d0;
  --md-inverse-surface: #322f35;
  --md-inverse-on-surface: #f5eff7;
  --md-scrim: rgba(0, 0, 0, 0.4);

  /* M3 shape scale */
  --md-shape-xs: 4px;
  --md-shape-sm: 8px;
  --md-shape-md: 12px;
  --md-shape-lg: 16px;
  --md-shape-xl: 28px;
  --md-shape-full: 999px;

  /* M3 elevation */
  --md-elevation-1: 0 1px 2px rgba(0, 0, 0, 0.3),
    0 1px 3px 1px rgba(0, 0, 0, 0.15);
  --md-elevation-2: 0 1px 2px rgba(0, 0, 0, 0.3),
    0 2px 6px 2px rgba(0, 0, 0, 0.15);
  --md-elevation-3: 0 4px 8px 3px rgba(0, 0, 0, 0.15),
    0 1px 3px rgba(0, 0, 0, 0.3);

  /* Motion */
  --md-motion-short: 150ms;
  --md-motion-medium: 250ms;
  --md-motion-easing: cubic-bezier(0.2, 0, 0, 1);

  /*
   * CJK-safe stack: Latin faces first, then Hong Kong Traditional Chinese
   * faces so playful Cantonese copy never falls back to a Simplified or
   * Japanese glyph set.
   */
  --md-font-plain: 'Segoe UI Variable Text', 'Segoe UI', system-ui,
    -apple-system, 'Noto Sans', Roboto, 'Microsoft JhengHei UI',
    'Microsoft JhengHei', 'PingFang HK', 'Noto Sans CJK HK', 'Noto Sans HK',
    'Hiragino Sans CNS', sans-serif;
  --md-font-mono: 'Cascadia Mono', 'Cascadia Code', Consolas, 'SFMono-Regular',
    'Noto Sans Mono', 'Liberation Mono', monospace;
}

/* Dark scheme when the reader's system asks for it and no manual override wins. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) {
    color-scheme: dark;
    --md-primary: #d0bcff;
    --md-on-primary: #381e72;
    --md-primary-container: #4f378b;
    --md-on-primary-container: #eaddff;
    --md-secondary: #ccc2dc;
    --md-on-secondary: #332d41;
    --md-secondary-container: #4a4458;
    --md-on-secondary-container: #e8def8;
    --md-tertiary: #efb8c8;
    --md-on-tertiary: #492532;
    --md-tertiary-container: #633b48;
    --md-on-tertiary-container: #ffd8e4;
    --md-error: #f2b8b5;
    --md-on-error: #601410;
    --md-error-container: #8c1d18;
    --md-on-error-container: #f9dedc;
    --md-surface: #141218;
    --md-on-surface: #e6e0e9;
    --md-surface-variant: #49454f;
    --md-on-surface-variant: #cac4d0;
    --md-surface-container-lowest: #0f0d13;
    --md-surface-container-low: #1d1b20;
    --md-surface-container: #211f26;
    --md-surface-container-high: #2b2930;
    --md-surface-container-highest: #36343b;
    --md-outline: #948f99;
    --md-outline-variant: #49454f;
    --md-inverse-surface: #e6e0e9;
    --md-inverse-on-surface: #322f35;
    --md-scrim: rgba(0, 0, 0, 0.6);
  }
}

/* Manual override always wins over the system preference. */
:root[data-theme='dark'] {
  color-scheme: dark;
  --md-primary: #d0bcff;
  --md-on-primary: #381e72;
  --md-primary-container: #4f378b;
  --md-on-primary-container: #eaddff;
  --md-secondary: #ccc2dc;
  --md-on-secondary: #332d41;
  --md-secondary-container: #4a4458;
  --md-on-secondary-container: #e8def8;
  --md-tertiary: #efb8c8;
  --md-on-tertiary: #492532;
  --md-tertiary-container: #633b48;
  --md-on-tertiary-container: #ffd8e4;
  --md-error: #f2b8b5;
  --md-on-error: #601410;
  --md-error-container: #8c1d18;
  --md-on-error-container: #f9dedc;
  --md-surface: #141218;
  --md-on-surface: #e6e0e9;
  --md-surface-variant: #49454f;
  --md-on-surface-variant: #cac4d0;
  --md-surface-container-lowest: #0f0d13;
  --md-surface-container-low: #1d1b20;
  --md-surface-container: #211f26;
  --md-surface-container-high: #2b2930;
  --md-surface-container-highest: #36343b;
  --md-outline: #948f99;
  --md-outline-variant: #49454f;
  --md-inverse-surface: #e6e0e9;
  --md-inverse-on-surface: #322f35;
  --md-scrim: rgba(0, 0, 0, 0.6);
}

/*
 * Accent seeds. Each one only re-tones the primary role, so every surface,
 * outline and body colour keeps the contrast the baseline scheme was built
 * with. Light values come first; the dark values repeat under both the system
 * preference and the manual dark override, exactly like the base scheme.
 */
:root[data-accent='teal'] {
  --md-primary: #006a68;
  --md-on-primary: #ffffff;
  --md-primary-container: #6ff7f3;
  --md-on-primary-container: #00201f;
}

:root[data-accent='amber'] {
  --md-primary: #8b5000;
  --md-on-primary: #ffffff;
  --md-primary-container: #ffdcc0;
  --md-on-primary-container: #2d1600;
}

:root[data-accent='rose'] {
  --md-primary: #984061;
  --md-on-primary: #ffffff;
  --md-primary-container: #ffd9e2;
  --md-on-primary-container: #3e001d;
}

@media (prefers-color-scheme: dark) {
  :root[data-accent='teal']:not([data-theme='light']) {
    --md-primary: #4cdad5;
    --md-on-primary: #003736;
    --md-primary-container: #00504e;
    --md-on-primary-container: #6ff7f3;
  }

  :root[data-accent='amber']:not([data-theme='light']) {
    --md-primary: #ffb877;
    --md-on-primary: #4a2800;
    --md-primary-container: #6a3b00;
    --md-on-primary-container: #ffdcc0;
  }

  :root[data-accent='rose']:not([data-theme='light']) {
    --md-primary: #ffb1c8;
    --md-on-primary: #5e1133;
    --md-primary-container: #7b2949;
    --md-on-primary-container: #ffd9e2;
  }
}

:root[data-theme='dark'][data-accent='teal'] {
  --md-primary: #4cdad5;
  --md-on-primary: #003736;
  --md-primary-container: #00504e;
  --md-on-primary-container: #6ff7f3;
}

:root[data-theme='dark'][data-accent='amber'] {
  --md-primary: #ffb877;
  --md-on-primary: #4a2800;
  --md-primary-container: #6a3b00;
  --md-on-primary-container: #ffdcc0;
}

:root[data-theme='dark'][data-accent='rose'] {
  --md-primary: #ffb1c8;
  --md-on-primary: #5e1133;
  --md-primary-container: #7b2949;
  --md-on-primary-container: #ffd9e2;
}

/* ------------------------------------------------------------- base type */

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--md-surface);
  color: var(--md-on-surface);
  font-family: var(--md-font-plain);
  /* M3 body-large */
  font-size: 1rem;
  line-height: 1.5;
  letter-spacing: 0.03125rem;
  overflow-wrap: break-word;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 400;
  letter-spacing: 0;
}

/* M3 display-small */
.md-display {
  font-size: clamp(1.9rem, 1.35rem + 2.4vw, 2.25rem);
  line-height: 1.22;
  font-weight: 400;
}

/* M3 headline-medium / headline-small */
.md-headline {
  font-size: clamp(1.5rem, 1.24rem + 1.1vw, 1.75rem);
  line-height: 1.28;
}

.md-title-lg {
  font-size: 1.375rem;
  line-height: 1.27;
}

.md-title {
  font-size: 1rem;
  line-height: 1.5;
  font-weight: 500;
  letter-spacing: 0.009375rem;
}

.md-body {
  font-size: 0.875rem;
  line-height: 1.43;
  letter-spacing: 0.015625rem;
  color: var(--md-on-surface-variant);
}

.md-label {
  font-size: 0.6875rem;
  line-height: 1.45;
  font-weight: 500;
  letter-spacing: 0.03125rem;
  text-transform: uppercase;
}

a {
  color: var(--md-primary);
}

code,
kbd,
samp,
pre {
  font-family: var(--md-font-mono);
}

:where(a, button, input, select, textarea, summary, [tabindex]):focus-visible {
  outline: 3px solid var(--md-primary);
  outline-offset: 2px;
  border-radius: var(--md-shape-xs);
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: 0.5rem;
  top: -4rem;
  z-index: 60;
  padding: 0.75rem 1.25rem;
  border-radius: var(--md-shape-full);
  background: var(--md-primary);
  color: var(--md-on-primary);
  font-weight: 500;
  text-decoration: none;
  transition: top var(--md-motion-short) var(--md-motion-easing);
}

.skip-link:focus {
  top: 0.5rem;
}

/* -------------------------------------------------- bilingual text pairs */

.i18n-b {
  display: none;
}

:root[data-lang='bi'] .i18n-b {
  display: block;
  margin-top: 0.15em;
  font-size: 0.82em;
  line-height: 1.35;
  font-weight: 400;
  letter-spacing: 0;
  opacity: 0.78;
  text-transform: none;
}

:root[data-lang='bi'] .i18n-inline .i18n-b {
  display: inline;
  margin-top: 0;
  margin-inline-start: 0.4em;
}

:root[data-lang='bi'] .i18n-inline .i18n-b::before {
  content: '· ';
}

/* ------------------------------------------------------------ app bar */

.app-bar {
  position: sticky;
  top: 0;
  z-index: 30;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 0.75rem;
  padding: 0.6rem clamp(0.75rem, 0.4rem + 1.6vw, 1.5rem);
  background: var(--md-surface-container);
  border-bottom: 1px solid var(--md-outline-variant);
}

.app-bar__brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-inline-end: auto;
  min-width: 0;
  color: inherit;
  text-decoration: none;
}

.app-bar__mark {
  flex: none;
  display: grid;
  place-items: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--md-shape-md);
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
}

.app-bar__mark svg {
  width: 1.35rem;
  height: 1.35rem;
  fill: currentColor;
}

.app-bar__titles {
  min-width: 0;
}

.app-bar__title {
  font-size: 1.0625rem;
  font-weight: 500;
  line-height: 1.3;
}

.app-bar__subtitle {
  font-size: 0.75rem;
  line-height: 1.3;
  color: var(--md-on-surface-variant);
}

.app-bar nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
}

.app-bar__actions {
  display: flex;
  gap: 0.25rem;
}

/* ---------------------------------------------------------------- tabs */

/*
 * M3 primary tabs. Without JavaScript these are ordinary anchors to the
 * sections below, so they carry no selected state and every panel stays
 * visible. The controller adds the tablist roles, the selected state and the
 * `hidden` attribute on the panels that are not current.
 */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.15rem;
  padding: 0 clamp(0.5rem, 0.2rem + 1.4vw, 1.25rem);
  background: var(--md-surface-container);
  border-bottom: 1px solid var(--md-outline-variant);
}

.tab {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.25rem 0.4rem;
  min-height: 3rem;
  padding: 0.5rem 1rem;
  border-bottom: 3px solid transparent;
  color: var(--md-on-surface-variant);
  font-size: 0.875rem;
  font-weight: 500;
  line-height: 1.25;
  text-align: center;
  text-decoration: none;
  transition: background-color var(--md-motion-short) var(--md-motion-easing),
    color var(--md-motion-short) var(--md-motion-easing);
}

.tab:hover {
  background: color-mix(in srgb, var(--md-on-surface) 8%, transparent);
  color: var(--md-on-surface);
}

.tab[aria-selected='true'] {
  color: var(--md-primary);
  border-bottom-color: var(--md-primary);
}

/* Secondary tabs inside a panel: one category or section at a time. */
.subtabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--md-outline-variant);
}

.subtab {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.2rem 0.4rem;
  min-height: 2.5rem;
  padding: 0.4rem 0.9rem;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-full);
  background: var(--md-surface-container-low);
  color: var(--md-on-surface-variant);
  font-size: 0.8125rem;
  font-weight: 500;
  line-height: 1.3;
  text-decoration: none;
}

.subtab:hover {
  background: var(--md-surface-container-high);
  color: var(--md-on-surface);
}

.subtab[aria-selected='true'] {
  background: var(--md-secondary-container);
  border-color: transparent;
  color: var(--md-on-secondary-container);
}

.tab-panel[hidden],
.subpanel[hidden] {
  display: none;
}

.nojs-note {
  max-width: 74rem;
  margin: 0 auto;
  padding: 0.75rem clamp(0.75rem, 0.4rem + 1.6vw, 1.5rem);
  font-size: 0.8125rem;
  color: var(--md-on-surface-variant);
}

.nojs-note span {
  display: block;
}

:root[data-js='on'] .nojs-note {
  display: none;
}

/* ------------------------------------------------------- generated lists */

.doc-list {
  display: grid;
  gap: 0.6rem;
  margin: 1rem 0 0;
  padding: 0;
  list-style: none;
}

.doc-link {
  display: block;
  padding: 0.8rem 1rem;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-md);
  background: var(--md-surface-container-low);
  color: inherit;
  text-decoration: none;
}

.doc-link:hover {
  background: var(--md-surface-container);
}

.doc-link__title {
  display: block;
  font-size: 0.9375rem;
  font-weight: 500;
}

.doc-link__desc {
  display: block;
  margin-top: 0.2rem;
  font-size: 0.8125rem;
  color: var(--md-on-surface-variant);
}

.doc-link__path {
  display: block;
  margin-top: 0.35rem;
  font-family: var(--md-font-mono);
  font-size: 0.75rem;
  color: var(--md-on-surface-variant);
  overflow-wrap: anywhere;
}

.subpanel__meta {
  margin: 0.35rem 0 0;
}

/* --------------------------------------------------------- M3 buttons */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  /*
   * Bilingual mode puts an English and a Cantonese label inside one control.
   * Wrapping lets the pair stack instead of pushing the button past the
   * viewport at narrow widths.
   */
  flex-wrap: wrap;
  max-width: 100%;
  gap: 0.25rem 0.5rem;
  min-height: 2.5rem;
  padding: 0.5rem 1.5rem;
  border: 0;
  border-radius: var(--md-shape-full);
  font-family: inherit;
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.00625rem;
  line-height: 1.25;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  transition: background-color var(--md-motion-short) var(--md-motion-easing),
    box-shadow var(--md-motion-short) var(--md-motion-easing);
}

.btn--filled {
  background: var(--md-primary);
  color: var(--md-on-primary);
}

.btn--filled:hover {
  box-shadow: var(--md-elevation-1);
}

.btn--tonal {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}

.btn--tonal:hover {
  box-shadow: var(--md-elevation-1);
}

.btn--outlined {
  background: transparent;
  color: var(--md-primary);
  border: 1px solid var(--md-outline);
}

.btn--outlined:hover {
  background: color-mix(in srgb, var(--md-primary) 8%, transparent);
}

.btn--text {
  padding-inline: 0.75rem;
  background: transparent;
  color: var(--md-primary);
}

.btn--text:hover {
  background: color-mix(in srgb, var(--md-primary) 8%, transparent);
}

.btn--icon {
  min-width: 2.5rem;
  padding: 0.5rem;
  background: transparent;
  color: var(--md-on-surface-variant);
}

.btn--icon:hover {
  background: color-mix(in srgb, var(--md-on-surface) 8%, transparent);
}

.btn--icon svg {
  width: 1.25rem;
  height: 1.25rem;
  fill: currentColor;
}

.btn--small {
  min-height: 2.25rem;
  padding: 0.375rem 1rem;
}

.btn[aria-pressed='true'] {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}

/* ------------------------------------------------------------- layout */

main {
  display: block;
}

.section {
  max-width: 74rem;
  margin: 0 auto;
  padding: clamp(2rem, 1.2rem + 3vw, 3.5rem)
    clamp(0.75rem, 0.4rem + 1.6vw, 1.5rem);
}

.section__head {
  margin-bottom: 1.5rem;
}

.section__head p {
  margin: 0.5rem 0 0;
  max-width: 60ch;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 0.5rem;
  padding: 0.2rem 0.7rem;
  border-radius: var(--md-shape-full);
  background: var(--md-tertiary-container);
  color: var(--md-on-tertiary-container);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.05rem;
  text-transform: uppercase;
}

/* --------------------------------------------------------------- hero */

.hero {
  background: radial-gradient(
      120% 120% at 15% 0%,
      color-mix(in srgb, var(--md-primary) 16%, transparent) 0%,
      transparent 60%
    ),
    var(--md-surface-container-low);
  border-bottom: 1px solid var(--md-outline-variant);
}

.hero__inner {
  max-width: 74rem;
  margin: 0 auto;
  padding: clamp(2.25rem, 1.4rem + 3.5vw, 4.5rem)
    clamp(0.75rem, 0.4rem + 1.6vw, 1.5rem);
}

.hero__lead {
  margin: 1rem 0 0;
  max-width: 62ch;
  font-size: 1.0625rem;
  line-height: 1.55;
  color: var(--md-on-surface-variant);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
}

.hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1.75rem 0 0;
  padding: 0;
  list-style: none;
}

.hero__facts li {
  padding: 0.35rem 0.85rem;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-full);
  background: var(--md-surface-container-lowest);
  font-size: 0.8125rem;
  color: var(--md-on-surface-variant);
}

/* -------------------------------------------------------------- cards */

.card-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 17rem), 1fr));
  margin: 0;
  padding: 0;
  list-style: none;
}

.card {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  height: 100%;
  padding: 1.125rem 1.25rem 1.25rem;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-lg);
  background: var(--md-surface-container-low);
  color: inherit;
  text-decoration: none;
  transition: box-shadow var(--md-motion-medium) var(--md-motion-easing),
    background-color var(--md-motion-medium) var(--md-motion-easing),
    transform var(--md-motion-medium) var(--md-motion-easing);
}

a.card:hover {
  background: var(--md-surface-container);
  box-shadow: var(--md-elevation-2);
  transform: translateY(-2px);
}

.card__kicker {
  color: var(--md-primary);
}

.card__title {
  display: block;
  font-size: 1.0625rem;
  font-weight: 500;
  line-height: 1.35;
}

.card__body {
  display: block;
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.45;
  color: var(--md-on-surface-variant);
}

.card__meta {
  display: block;
  margin-top: auto;
  padding-top: 0.65rem;
  font-family: var(--md-font-mono);
  font-size: 0.75rem;
  color: var(--md-on-surface-variant);
  overflow-wrap: anywhere;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1rem;
}

/* --------------------------------------------------------- code block */

.code {
  position: relative;
  margin: 0.9rem 0 0;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-md);
  background: var(--md-surface-container-highest);
}

.code pre {
  margin: 0;
  padding: 0.9rem 1rem;
  overflow-x: auto;
  font-size: 0.8125rem;
  line-height: 1.55;
}

.code__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding: 0.4rem 0.5rem 0.4rem 1rem;
  border-bottom: 1px solid var(--md-outline-variant);
  font-size: 0.75rem;
  color: var(--md-on-surface-variant);
}

/* ------------------------------------------------------------ panels */

.panel {
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-lg);
  background: var(--md-surface-container-low);
  padding: 1.25rem;
}

.panel + .panel {
  margin-top: 1rem;
}

.field {
  display: block;
  margin-bottom: 0.85rem;
}

.field > span {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--md-on-surface-variant);
}

.text-input,
.textarea {
  width: 100%;
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--md-outline);
  border-radius: var(--md-shape-sm);
  background: var(--md-surface-container-lowest);
  color: var(--md-on-surface);
  font-family: inherit;
  font-size: 0.9375rem;
  line-height: 1.4;
}

.textarea,
.text-input--mono {
  font-family: var(--md-font-mono);
  font-size: 0.875rem;
}

.textarea {
  min-height: 6.5rem;
  resize: vertical;
}

.text-input[aria-invalid='true'] {
  border-color: var(--md-error);
  border-width: 2px;
}

/* ------------------------------------------------------------ search */

/*
 * The search dock sits outside the tab panels, so the search box, the regex
 * builder and the results are reachable from every tab without scrolling back
 * to a dedicated search page.
 */
.dock {
  border-bottom: 1px solid var(--md-outline-variant);
  background: var(--md-surface-container-low);
}

.dock__inner {
  max-width: 74rem;
  margin: 0 auto;
  padding: 1rem clamp(0.75rem, 0.4rem + 1.6vw, 1.5rem);
}

.search-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
  padding: 0.6rem;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-xl);
  background: var(--md-surface-container-high);
}

.search-bar__field {
  display: flex;
  flex: 1 1 14rem;
  align-items: center;
  gap: 0.5rem;
  min-width: 0;
  padding-inline-start: 0.75rem;
}

.search-bar__field svg {
  flex: none;
  width: 1.25rem;
  height: 1.25rem;
  fill: var(--md-on-surface-variant);
}

.search-bar__field input {
  flex: 1 1 auto;
  min-width: 0;
  padding: 0.6rem 0;
  border: 0;
  background: transparent;
  color: var(--md-on-surface);
  font-family: inherit;
  font-size: 1rem;
}

.search-bar__field input:focus {
  outline: none;
}

.search-bar__field:focus-within {
  border-radius: var(--md-shape-full);
  outline: 3px solid var(--md-primary);
  outline-offset: 2px;
}

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

.search-note {
  margin: 0.6rem 0 0;
  font-size: 0.8125rem;
  color: var(--md-on-surface-variant);
}

.search-status {
  margin: 1rem 0 0.5rem;
  font-size: 0.875rem;
  font-weight: 500;
}

.search-status[data-tone='error'] {
  color: var(--md-error);
}

.results {
  display: grid;
  gap: 0.6rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.result {
  display: block;
  padding: 0.85rem 1rem;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-md);
  background: var(--md-surface-container-low);
  color: inherit;
  text-decoration: none;
}

.result:hover {
  background: var(--md-surface-container);
}

.result__title {
  font-size: 1rem;
  font-weight: 500;
}

.result__path {
  font-family: var(--md-font-mono);
  font-size: 0.75rem;
  color: var(--md-on-surface-variant);
  word-break: break-all;
}

.result__desc {
  margin: 0.3rem 0 0;
  font-size: 0.8125rem;
  color: var(--md-on-surface-variant);
}

.result mark {
  padding: 0 0.1em;
  border-radius: 3px;
  background: var(--md-tertiary-container);
  color: var(--md-on-tertiary-container);
}

/* ---------------------------------------------------- regex builder */

.builder[hidden] {
  display: none;
}

.builder {
  margin-top: 1rem;
}

.builder__grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 20rem), 1fr));
}

.token-group {
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-md);
  background: var(--md-surface-container-lowest);
  padding: 0.75rem 0.85rem;
}

.token-group > h4 {
  margin-bottom: 0.5rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--md-on-surface-variant);
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.chip {
  min-height: 2rem;
  padding: 0.3rem 0.7rem;
  border: 1px solid var(--md-outline);
  border-radius: var(--md-shape-sm);
  background: var(--md-surface-container-lowest);
  color: var(--md-on-surface);
  font-family: var(--md-font-mono);
  font-size: 0.8125rem;
  cursor: pointer;
}

.chip:hover {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}

.inline-form {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: center;
  margin-top: 0.5rem;
}

.inline-form .text-input {
  flex: 1 1 8rem;
  min-width: 0;
  padding: 0.4rem 0.6rem;
  font-size: 0.8125rem;
}

.checkbox-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1rem;
}

.checkbox {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.875rem;
}

.checkbox input {
  width: 1.15rem;
  height: 1.15rem;
  accent-color: var(--md-primary);
}

.feedback {
  margin: 0.75rem 0 0;
  padding: 0.6rem 0.85rem;
  border-radius: var(--md-shape-sm);
  font-size: 0.8125rem;
  background: var(--md-surface-container-high);
  color: var(--md-on-surface-variant);
}

.feedback[data-tone='error'] {
  background: var(--md-error-container);
  color: var(--md-on-error-container);
}

.feedback[data-tone='warn'] {
  background: var(--md-tertiary-container);
  color: var(--md-on-tertiary-container);
}

.matches {
  margin: 0.75rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.5rem;
  max-height: 20rem;
  overflow: auto;
}

.matches li {
  padding: 0.5rem 0.7rem;
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--md-shape-sm);
  background: var(--md-surface-container-lowest);
  font-family: var(--md-font-mono);
  font-size: 0.8125rem;
  overflow-wrap: anywhere;
}

.matches .group {
  display: block;
  color: var(--md-on-surface-variant);
}

/* ------------------------------------------------------ preferences */

.prefs[hidden] {
  display: none;
}

.prefs {
  border-bottom: 1px solid var(--md-outline-variant);
  background: var(--md-surface-container-low);
}

.prefs__inner {
  max-width: 74rem;
  margin: 0 auto;
  padding: 1.25rem clamp(0.75rem, 0.4rem + 1.6vw, 1.5rem);
  display: grid;
  gap: 1.25rem;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 16rem), 1fr));
}

.prefs fieldset {
  margin: 0;
  padding: 0;
  border: 0;
  min-width: 0;
}

.prefs legend {
  padding: 0;
  margin-bottom: 0.5rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--md-on-surface-variant);
}

.slider-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.slider-row input[type='range'] {
  flex: 1 1 auto;
  min-width: 0;
  accent-color: var(--md-primary);
  height: 1.5rem;
}

.slider-row output {
  flex: none;
  min-width: 8.5rem;
  font-size: 0.8125rem;
  color: var(--md-on-surface-variant);
}

/* ------------------------------------------------------------ toasts */

.toasts {
  position: fixed;
  right: 1rem;
  bottom: 1rem;
  z-index: 50;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  width: min(24rem, calc(100vw - 2rem));
  pointer-events: none;
}

.toast {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.85rem 0.85rem 0.85rem 1rem;
  border-radius: var(--md-shape-md);
  background: var(--md-inverse-surface);
  color: var(--md-inverse-on-surface);
  box-shadow: var(--md-elevation-3);
  pointer-events: auto;
  animation: toast-in var(--md-motion-medium) var(--md-motion-easing);
}

.toast[data-tone='error'] {
  background: var(--md-error-container);
  color: var(--md-on-error-container);
  border: 1px solid var(--md-error);
}

.toast__text {
  flex: 1 1 auto;
  min-width: 0;
  font-size: 0.875rem;
  line-height: 1.4;
}

.toast__title {
  font-weight: 500;
}

.toast__close {
  flex: none;
  min-width: 2.25rem;
  min-height: 2.25rem;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: var(--md-shape-full);
  background: transparent;
  color: inherit;
  font-size: 1rem;
  cursor: pointer;
}

.toast__close:hover {
  background: color-mix(in srgb, currentColor 14%, transparent);
}

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

/* ------------------------------------------------------------ footer */

.site-footer {
  border-top: 1px solid var(--md-outline-variant);
  background: var(--md-surface-container-low);
}

.site-footer__inner {
  max-width: 74rem;
  margin: 0 auto;
  padding: 2rem clamp(0.75rem, 0.4rem + 1.6vw, 1.5rem);
  display: grid;
  gap: 1rem;
}

.link-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.25rem;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 0.875rem;
}

/* ------------------------------------------------------------ density */

/*
 * Compact density removes whitespace only. Control heights, hit targets and
 * font sizes are untouched, so a denser page never costs a reader a usable
 * click or touch target.
 */
:root[data-density='compact'] .section {
  padding-block: clamp(1.1rem, 0.7rem + 1.4vw, 1.75rem);
}

:root[data-density='compact'] .hero__inner {
  padding-block: clamp(1.4rem, 0.9rem + 1.8vw, 2.5rem);
}

:root[data-density='compact'] .dock__inner {
  padding-block: 0.6rem;
}

:root[data-density='compact'] .prefs__inner {
  padding-block: 0.85rem;
}

:root[data-density='compact'] .card-grid,
:root[data-density='compact'] .doc-list {
  gap: 0.5rem;
}

:root[data-density='compact'] .card {
  padding: 0.8rem 0.95rem;
}

:root[data-density='compact'] .doc-link {
  padding: 0.55rem 0.75rem;
}

:root[data-density='compact'] .panel {
  padding: 0.9rem;
}

:root[data-density='compact'] .section__head {
  margin-bottom: 1rem;
}

:root[data-density='compact'] .site-footer__inner {
  padding-block: 1.25rem;
}

/* --------------------------------------------------------- responsive */

@media (max-width: 34rem) {
  .app-bar {
    row-gap: 0.4rem;
  }

  .app-bar__brand {
    flex: 1 1 100%;
    margin-inline-end: 0;
  }

  .app-bar nav {
    flex: 1 1 auto;
  }

  .btn {
    padding-inline: 1rem;
  }

  .tab {
    flex: 1 1 auto;
    padding-inline: 0.6rem;
  }

  .subtab {
    padding-inline: 0.7rem;
  }

  .slider-row output {
    min-width: 6.5rem;
  }
}

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

  a.card:hover {
    transform: none;
  }
}

@media (forced-colors: active) {
  .card,
  .result,
  .panel,
  .toast,
  .doc-link,
  .subtab {
    border: 1px solid CanvasText;
  }

  /* Forced colours drop the accent underline, so name the current tab too. */
  .tab[aria-selected='true'],
  .subtab[aria-selected='true'] {
    border: 2px solid Highlight;
  }
}

@media print {
  .app-bar,
  .prefs,
  .toasts,
  .builder,
  .tabs,
  .subtabs,
  .dock {
    display: none !important;
  }

  /* Print the whole document, not just the tab that happened to be open. */
  .tab-panel[hidden],
  .subpanel[hidden] {
    display: block !important;
  }
}