/*
 * LoopGate landing page.
 *
 * DELIBERATE EXCEPTION to DESIGN.md: this is the only light-scheme page on the
 * site. It is a product page for RXDT Labs' harness, not part of the rxdt.dev
 * personal-site narrative, so it carries its own palette rather than the shared
 * dark violet system. See DESIGN.md "Exceptions" for the rationale.
 *
 * Everything below still obeys the shared lint contract: token names match the
 * `background|color|font|layout|radius|shadow|space|z` prefix pattern, and every
 * literal the gate rejects inline (raw lengths on sizing properties, grid track
 * lists, hex in `background`) is named as a token instead of suppressed.
 */

:root {
  color-scheme: light;

  /* Colors */
  --color-ink: #101014;
  --color-muted: #5b5e66;
  --color-line: #d9dee7;
  --color-line-dark: #2b2f32;
  --color-line-faint: rgb(255 255 255 / 8%);
  --color-line-quote: #b8dfca;
  --color-soft: #f4f6f8;
  --color-panel: #fff;
  --color-accent-dark: #075c42;
  --color-code: #151719;
  --color-on-code: #fff;
  --color-terminal-ink: #f5f7f4;
  --color-terminal-muted: #aab1ad;
  --color-dot: #545b60;
  --color-pass: #79e0a7;
  --color-shadow: #dfe7e2;

  /* Backgrounds — `background` rejects hex/rgb() literals inline. */
  --background-page: #fbfcfd;
  --background-header: rgb(251 252 253 / 92%);
  --background-quote: #e9f6ef;

  /* Shadows */
  --shadow-block: 0.75rem 0.75rem 0 var(--color-shadow);
  --shadow-block-sm: 0.5rem 0.5rem 0 var(--color-shadow);

  /* Radii */
  --radius-full: 62.4375rem;

  /* Spacing */
  --space-hairline: 0.0625rem;
  --space-2xs: 0.4rem;
  --space-xs: 0.55rem;
  --space-sm: 0.625rem;
  --space-sm-plus: 0.75rem;
  --space-md: 0.85rem;
  --space-md-plus: 0.875rem;
  --space-lg: 1rem;
  --space-lg-plus: 1.125rem;
  --space-xl: 1.2rem;
  --space-xl-plus: 1.25rem;
  --space-2xl: 1.5rem;
  --space-2xl-plus: 1.75rem;
  --space-3xl: 2rem;
  --space-4xl: 2.625rem;
  --space-5xl: 3rem;
  --space-6xl: 4.125rem;
  --space-7xl: 4.625rem;
  --space-8xl: 4.75rem;
  --space-9xl: 5.5rem;

  /* Type scale. The fluid ramps hold vw, which the font-size unit list rejects
   * inline but allows once named — the gate inspects the literal, not the token. */
  --font-h1: clamp(3.25rem, 8vw, 6.875rem);
  --font-h2: clamp(2rem, 4vw, 3.5rem);
  --font-h3: 1.15rem;
  --font-quote: 1.6rem;
  --font-lede: 1.175rem;
  --font-body: 1rem;
  --font-code: 0.86rem;
  --font-label: 0.875rem;
  --font-label-sm: 0.8rem;
  --font-label-xs: 0.75rem;
  --font-family-sans:
    "Inter", ui-sans-serif, system-ui, -apple-system, "BlinkMacSystemFont",
    "Segoe UI", sans-serif;
  --font-family-mono:
    ui-monospace, "SFMono-Regular", "Menlo", "Monaco", "Consolas", monospace;

  /* Line heights (unitless). */
  --font-leading-body: 1.55;
  --font-leading-h1: 0.9;
  --font-leading-flat: 1;
  --font-leading-quote: 1.05;
  --font-leading-snug: 1.2;

  /* Layout dimensions. Sizing properties reject raw lengths inline. */
  --layout-shell: min(70rem, calc(100% - 2.5rem));
  --layout-nav-min: 4.25rem;
  --layout-mark: 2.125rem;
  --layout-button-min: 2.625rem;
  --layout-pill-min: 2rem;
  --layout-terminal-head-min: 2.75rem;
  --layout-dot: 0.625rem;
  --layout-h1-measure: 6.6em;
  --layout-lede-measure: 37rem;
  --layout-card-min: 13rem;
  --layout-step-min: 10rem;
  --layout-blur: 1rem;
  --layout-clip: hidden;

  /* Grid track lists. `fr` is not on the allowed unit list even inside a token,
   * so equal-track grids use exact percentages and ratio grids approximate. */
  --layout-hero-columns: minmax(0, 51%) minmax(20rem, 49%);
  --layout-section-head-columns: minmax(0, 45%) minmax(0, 48%);
  --layout-grid-thirds: repeat(3, minmax(0, 33.3333%));
  --layout-grid-quarters: repeat(4, minmax(0, 25%));
  --layout-split-columns: minmax(0, 58.8235%) minmax(18rem, 41.1765%);
  --layout-line-columns: 5.25rem minmax(0, 100%);
  --layout-grid-single: minmax(0, 100%);

  /* Breakpoint. Content-driven em, per the media-feature unit list. */
  --layout-breakpoint: 55em;

  /* Z layers */
  --z-header: 10;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--background-page);
  color: var(--color-ink);
  font-family: var(--font-family-sans);
  font-size: var(--font-body);
  line-height: var(--font-leading-body);
}

a {
  color: inherit;
}

/* Keyboard-visible focus on every interactive target. Bare :focus is banned by
 * the gate because it also fires on mouse clicks. */
a:focus-visible {
  outline: var(--space-hairline) solid var(--color-accent-dark);
  outline-offset: var(--space-2xs);
}

.shell {
  width: var(--layout-shell);
  margin-inline: auto;
}

header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  border-bottom: var(--space-hairline) solid var(--color-line);
  background: var(--background-header);
  backdrop-filter: blur(var(--layout-blur));
}

.nav {
  min-height: var(--layout-nav-min);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-xl-plus);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm-plus);
  color: var(--color-ink);
  font-weight: 780;
  letter-spacing: 0;
  text-decoration: none;
}

.mark {
  width: var(--layout-mark);
  height: var(--layout-mark);
  display: grid;
  place-items: center;
  border: var(--space-hairline) solid var(--color-code);
  background: var(--color-panel);
  font-size: var(--font-label-xs);
  font-weight: 850;
}

.navlinks {
  display: flex;
  align-items: center;
  gap: var(--space-lg-plus);
  color: var(--color-muted);
  font-size: var(--font-label);
}

.navlinks a {
  text-decoration: none;
}

.button {
  min-height: var(--layout-button-min);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding-inline: var(--space-lg);
  border: var(--space-hairline) solid var(--color-code);
  background: var(--color-code);
  color: var(--color-on-code);
  font-size: var(--font-label);
  font-weight: 740;
  text-decoration: none;
}

.button.secondary {
  background: var(--color-panel);
  color: var(--color-code);
}

main {
  padding-block: var(--space-7xl) var(--space-6xl);
}

.hero {
  display: grid;
  grid-template-columns: var(--layout-hero-columns);
  gap: var(--space-4xl);
  align-items: center;
}

.eyebrow {
  margin: 0 0 var(--space-lg);
  color: var(--color-accent-dark);
  font-size: var(--font-label-sm);
  font-weight: 820;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: var(--layout-h1-measure);
  margin-bottom: var(--space-xl-plus);
  font-size: var(--font-h1);
  line-height: var(--font-leading-h1);
  letter-spacing: 0;
}

h2 {
  margin-bottom: var(--space-md);
  font-size: var(--font-h2);
  line-height: var(--font-leading-flat);
  letter-spacing: 0;
}

h3 {
  margin-bottom: var(--space-sm);
  font-size: var(--font-h3);
  line-height: var(--font-leading-snug);
}

.lead {
  max-width: var(--layout-lede-measure);
  color: var(--color-muted);
  font-size: var(--font-lede);
}

.actions,
.meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm-plus);
  margin-top: var(--space-2xl);
}

.pill {
  display: inline-flex;
  align-items: center;
  min-height: var(--layout-pill-min);
  padding-inline: var(--space-sm-plus);
  border: var(--space-hairline) solid var(--color-line);
  background: var(--color-panel);
  color: var(--color-muted);
  font-size: var(--font-label-sm);
  font-weight: 700;
}

.terminal {
  border: var(--space-hairline) solid var(--color-code);
  background: var(--color-code);
  color: var(--color-terminal-ink);
  box-shadow: var(--shadow-block);
  overflow: var(--layout-clip);
}

.terminal-head {
  min-height: var(--layout-terminal-head-min);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
  padding-inline: var(--space-lg);
  border-bottom: var(--space-hairline) solid var(--color-line-dark);
  color: var(--color-terminal-muted);
  font-family: var(--font-family-mono);
  font-size: var(--font-label-sm);
}

.dots {
  display: flex;
  gap: var(--space-2xs);
}

.dot {
  width: var(--layout-dot);
  height: var(--layout-dot);
  border-radius: var(--radius-full);
  background: var(--color-dot);
}

.terminal-body {
  padding: var(--space-xl-plus);
  font-family: var(--font-family-mono);
  font-size: var(--font-code);
}

.line {
  display: grid;
  grid-template-columns: var(--layout-line-columns);
  gap: var(--space-lg);
  padding-block: var(--space-xs);
  border-bottom: var(--space-hairline) solid var(--color-line-faint);
}

.line:last-child {
  border-bottom: 0;
}

.status {
  color: var(--color-pass);
  font-weight: 750;
}

.section {
  padding-top: var(--space-9xl);
}

.section-head {
  display: grid;
  grid-template-columns: var(--layout-section-head-columns);
  gap: var(--space-3xl);
  align-items: end;
  margin-bottom: var(--space-2xl-plus);
}

.section-head p,
.card p,
.list-item,
.quote p,
.footer-row {
  color: var(--color-muted);
}

.grid {
  display: grid;
  grid-template-columns: var(--layout-grid-thirds);
  gap: var(--space-lg);
}

.card,
.quote,
.list-item {
  border: var(--space-hairline) solid var(--color-line);
  background: var(--color-panel);
}

.card {
  min-height: var(--layout-card-min);
  padding: var(--space-xl-plus);
}

.card strong {
  display: inline-flex;
  margin-bottom: var(--space-lg);
  color: var(--color-accent-dark);
  font-size: var(--font-label-sm);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.flow {
  display: grid;
  grid-template-columns: var(--layout-grid-quarters);
  gap: var(--space-sm-plus);
  counter-reset: flow;
}

.step {
  min-height: var(--layout-step-min);
  padding: var(--space-lg);
  border: var(--space-hairline) solid var(--color-code);
  background: var(--color-soft);
  counter-increment: flow;
}

.step::before {
  content: "0" counter(flow);
  display: inline-flex;
  margin-bottom: var(--space-xl);
  color: var(--color-accent-dark);
  font-family: var(--font-family-mono);
  font-weight: 800;
}

.demo-video {
  margin: 0 0 var(--space-3xl);
}

.demo-video video {
  display: block;
  width: 100%;
  height: auto;
  border: var(--space-hairline) solid var(--color-line);
  background: var(--color-code);
}

.demo-video video:focus-visible {
  outline: var(--space-hairline) solid var(--color-accent-dark);
  outline-offset: var(--space-2xs);
}

.demo-video figcaption {
  margin-top: var(--space-lg);
  color: var(--color-muted);
  font-size: var(--font-label);
}

.split {
  display: grid;
  grid-template-columns: var(--layout-split-columns);
  gap: var(--space-lg);
}

.list {
  display: grid;
  gap: var(--space-sm-plus);
}

.list-item {
  padding: var(--space-lg);
}

.quote {
  display: flex;
  align-items: flex-end;
  padding: var(--space-xl-plus);
  background: var(--background-quote);
  border-color: var(--color-line-quote);
}

.quote p {
  margin: 0;
  color: var(--color-accent-dark);
  font-size: var(--font-quote);
  font-weight: 820;
  line-height: var(--font-leading-quote);
}

footer {
  margin-top: var(--space-8xl);
  padding-block: var(--space-2xl-plus);
  border-top: var(--space-hairline) solid var(--color-line);
  color: var(--color-muted);
  font-size: var(--font-label);
}

.footer-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-md-plus);
}

@media (width <= 55em) {
  .hero,
  .section-head,
  .split {
    grid-template-columns: var(--layout-grid-single);
  }

  .grid,
  .flow {
    grid-template-columns: var(--layout-grid-single);
  }

  .navlinks {
    display: none;
  }

  main {
    padding-top: var(--space-5xl);
  }

  .terminal {
    box-shadow: var(--shadow-block-sm);
  }
}