/* Backplane launch site. Tokens and rules from docs/site/BRIEF.md. */

:root {
  --bg: #f6f6f3;
  --surface: #ffffff;
  --sunken: #eeeee9;
  --border: #deded7;
  --border-strong: #c5c5bc;
  --ink: #1b1c1f;
  --muted: #585b63;
  --accent: #3a45c9;
  --accent-hover: #2f39a8;
  --accent-soft: #e8eafc;
  --on-accent: #ffffff;
  --signal: #1d6f47;
  --signal-soft: #e3f2ea;
  --warn: #8a5a00;
  --warn-soft: #fbf1dc;
  --grid-line: rgb(27 28 31 / 0.05);
  --shadow-sm: 0 1px 2px rgb(20 20 30 / 0.06);
  --shadow-md: 0 1px 2px rgb(20 20 30 / 0.05), 0 8px 24px rgb(20 20 30 / 0.06);
  --shadow-lg: 0 2px 4px rgb(58 69 201 / 0.06), 0 16px 32px rgb(58 69 201 / 0.08),
    0 32px 64px rgb(20 20 30 / 0.1);

  --font-display: Newsreader, "Iowan Old Style", Charter, Georgia, serif;
  --font-body: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --h1: clamp(2.6rem, 1.6rem + 4.6vw, 5.25rem);
  --h2: clamp(1.9rem, 1.3rem + 2.4vw, 3.1rem);
  --gutter: clamp(20px, 5vw, 48px);
  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
  --spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1013;
    --surface: #17181c;
    --sunken: #1f2025;
    --border: #2c2e34;
    --border-strong: #3d4048;
    --ink: #e9e9e6;
    --muted: #a3a6ae;
    --accent: #9aa5ff;
    --accent-hover: #b4bcff;
    --accent-soft: #262a4d;
    --on-accent: #121433;
    --signal: #6fd6a2;
    --signal-soft: #16301f;
    --warn: #f2c46d;
    --warn-soft: #33280f;
    --grid-line: rgb(233 233 230 / 0.04);
    --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.4);
    --shadow-md: 0 1px 2px rgb(0 0 0 / 0.4), 0 8px 24px rgb(0 0 0 / 0.35);
    --shadow-lg: 0 2px 4px rgb(0 0 0 / 0.4), 0 24px 64px rgb(0 0 0 / 0.55);
  }
}

/* ---------- Base ---------- */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background-color: var(--bg);
  background-image: linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 24px 24px;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
}

h1,
h2,
h3,
p,
ul,
ol,
dl,
dd,
pre,
figure {
  margin: 0;
}

ul,
ol {
  padding: 0;
  list-style: none;
}

h1,
h2 {
  font-family: var(--font-display);
  font-weight: 500;
  letter-spacing: -0.025em;
  font-optical-sizing: auto;
  text-wrap: balance;
}

h1 {
  font-size: var(--h1);
  line-height: 1.05;
}

h2 {
  font-size: var(--h2);
  line-height: 1.15;
  max-width: 22ch;
}

h1 em,
h2 em {
  font-style: italic;
  font-weight: 500;
}

h1 em {
  color: var(--accent);
}

h3 {
  font-family: var(--font-body);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

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

a {
  color: var(--accent);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.wrap {
  width: 100%;
  max-width: calc(1160px + 2 * var(--gutter));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  padding-block: clamp(72px, 10vw, 140px);
}

.eyebrow,
.label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.eyebrow {
  margin-bottom: 18px;
}

.intro,
.prose p {
  max-width: 62ch;
  color: var(--muted);
  margin-top: 20px;
}

.intro {
  max-width: 56ch;
}

.prose.narrow p {
  max-width: 58ch;
}

.intro em {
  color: var(--warn);
  font-style: normal;
  font-weight: 500;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  padding: 24px;
}

.sig {
  color: var(--signal);
}

/* ---------- Interactive states ---------- */

a,
button {
  -webkit-tap-highlight-color: transparent;
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

a:active,
button:active {
  transform: translateY(1px) scale(0.98);
}

.skip {
  position: absolute;
  left: 12px;
  top: -60px;
  z-index: 100;
  padding: 12px 16px;
  background: var(--accent);
  color: var(--on-accent);
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  text-decoration: none;
  transition: top 150ms var(--ease);
}

.skip:focus {
  top: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border-radius: 8px;
  border: 1px solid transparent;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition:
    background-color 150ms var(--ease),
    border-color 150ms var(--ease),
    color 150ms var(--ease),
    box-shadow 150ms var(--ease),
    transform 120ms var(--ease);
}

.btn-lg {
  min-height: 52px;
  padding: 0 24px;
  font-size: 0.9375rem;
}

.btn-primary {
  background: var(--accent);
  color: var(--on-accent);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: var(--accent-hover);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: transparent;
  color: var(--ink);
  border-color: var(--border-strong);
}

.btn-secondary:hover {
  border-color: var(--ink);
  background-color: var(--surface);
}

.text-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  font-weight: 500;
  text-decoration: underline;
  text-decoration-color: transparent;
  text-underline-offset: 4px;
  transition:
    color 150ms var(--ease),
    text-decoration-color 150ms var(--ease);
}

.text-link:hover {
  color: var(--accent-hover);
  text-decoration-color: currentColor;
}

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: 64px;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 200ms var(--ease);
}

.site-header.is-scrolled {
  border-bottom-color: var(--border);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  color: var(--ink);
  text-decoration: none;
  border-radius: 8px;
}

.logo {
  flex: none;
  display: block;
}

.wordmark {
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: -0.01em;
}

.nav {
  display: none;
  gap: 4px;
}

.nav a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 12px;
  border-radius: 6px;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  text-decoration: none;
  transition:
    color 150ms var(--ease),
    background-color 150ms var(--ease);
}

.nav a:hover {
  color: var(--ink);
  background-color: var(--sunken);
}

.btn-header .long {
  display: none;
}

@media (min-width: 860px) {
  .nav {
    display: flex;
  }
  .btn-header .long {
    display: inline;
  }
  .btn-header .short {
    display: none;
  }
}

/* ---------- Theme palettes (fixed, from src/preview/themes.ts) ---------- */

.th {
  --t-mono: var(--font-mono);
  --t-sans: var(--font-body);
  --t-serif: Charter, "Iowan Old Style", Georgia, serif;
  background-color: var(--t-bg);
  color: var(--t-text);
  border: 1px solid var(--t-border);
  font-family: var(--t-body);
  transition:
    background-color 300ms var(--ease),
    color 300ms var(--ease),
    border-color 300ms var(--ease);
}

.th * {
  transition:
    background-color 300ms var(--ease),
    color 300ms var(--ease),
    border-color 300ms var(--ease);
}

.th[data-theme="terminal"] {
  --t-bg: #0b0f0c;
  --t-surface: #121a15;
  --t-text: #d8e6dc;
  --t-muted: #8ea597;
  --t-accent: #4ade80;
  --t-border: #1f2e25;
  --t-heading: var(--t-mono);
  --t-body: var(--t-sans);
  --t-prefix: "$ ";
  background-image: none;
}

.th[data-theme="paper"] {
  --t-bg: #f7f3ea;
  --t-surface: #fffdf8;
  --t-text: #1f1b16;
  --t-muted: #5b544a;
  --t-accent: #1f4fb8;
  --t-border: #e2d9c7;
  --t-heading: var(--t-serif);
  --t-body: var(--t-serif);
  --t-prefix: "§ ";
  background-image: none;
}

.th[data-theme="blueprint"] {
  --t-bg: #0b2545;
  --t-surface: #0f2e55;
  --t-text: #ffffff;
  --t-muted: #b8cbe6;
  --t-accent: #5ee7ff;
  --t-border: #1f4677;
  --t-heading: var(--t-sans);
  --t-body: var(--t-sans);
  --t-prefix: "// ";
  background-image: linear-gradient(rgb(94 231 255 / 0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgb(94 231 255 / 0.08) 1px, transparent 1px),
    linear-gradient(rgb(94 231 255 / 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgb(94 231 255 / 0.04) 1px, transparent 1px);
  background-size:
    80px 80px,
    80px 80px,
    16px 16px,
    16px 16px;
}

.mini-name {
  font-family: var(--t-heading);
  font-weight: 600;
  font-size: 1.375rem;
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.th[data-theme="terminal"] .mini-name::before {
  content: "> ";
  color: var(--t-accent);
}

.th[data-theme="blueprint"] .mini-name {
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.mini-head {
  color: var(--t-muted);
  font-size: 0.875rem;
  margin-top: 2px;
}

.mini-nav {
  margin-top: 14px;
  padding-block: 8px;
  border-block: 1px solid var(--t-border);
  font-family: var(--t-mono);
  font-size: 0.6875rem;
  color: var(--t-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.mini-eyebrow {
  margin-top: 20px;
  font-family: var(--t-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: var(--t-accent);
}

.mini-eyebrow::before {
  content: var(--t-prefix);
}

.mini-title {
  margin-top: 6px;
  font-family: var(--t-heading);
  font-size: 1.0625rem;
  font-weight: 600;
  line-height: 1.3;
}

.th[data-theme="paper"] .mini-title,
.th[data-theme="paper"] .ex-sec-title {
  font-style: italic;
}

.mini-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 12px;
}

.mini-pills span {
  font-family: var(--t-mono);
  font-size: 0.6875rem;
  padding: 3px 8px;
  border: 1px solid var(--t-border);
  border-radius: 999px;
  background: var(--t-surface);
}

.mini-result {
  margin-top: 18px;
  font-family: var(--t-mono);
  font-size: 0.75rem;
  color: var(--t-muted);
}

.mini-result .row {
  display: block;
  margin-top: 2px;
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--t-text);
  letter-spacing: -0.02em;
}

.mini-result b {
  font-weight: 500;
  color: var(--t-accent);
}

.glow {
  text-shadow:
    0 0 12px rgb(74 222 128 / 0.55),
    0 0 28px rgb(74 222 128 / 0.3);
}

/* ---------- Hero ---------- */

.hero {
  display: flex;
  align-items: center;
  min-height: min(92vh, 860px);
  padding-block: 48px 72px;
}

.hero-grid {
  display: grid;
  gap: 48px;
  align-items: center;
}

.hero-copy .lede {
  margin-top: 24px;
  max-width: 52ch;
  color: var(--muted);
  font-size: 1.125rem;
}

.actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 32px;
}

.fine {
  margin-top: 16px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--muted);
}

.fan-clip {
  overflow: clip;
  margin-inline: calc(-1 * var(--gutter));
  padding-block: 24px;
}

.fan {
  --rm: 0.5;
  --cs: 0.78;
  --p: 0;
  position: relative;
  height: 420px;
  perspective: 1200px;
}

.plane {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 340px;
  height: 420px;
  margin: -210px 0 0 -170px;
  will-change: transform;
  transform: translate(var(--ox), calc(var(--oy) + var(--p) * var(--dy)))
    rotate(calc((var(--r) + var(--p) * var(--open)) * var(--rm))) scale(calc(var(--cs) * var(--s, 1)));
}

.plane-back {
  --ox: -28px;
  --oy: -22px;
  --r: -6deg;
  --open: -1.5deg;
  --dy: -24px;
  --s: 0.92;
}

.plane-mid {
  --ox: 0px;
  --oy: 0px;
  --r: -2deg;
  --open: -1.5deg;
  --dy: -48px;
}

.plane-front {
  --ox: 28px;
  --oy: 24px;
  --r: 3deg;
  --open: 1.5deg;
  --dy: -80px;
}

.mini {
  width: 100%;
  height: 100%;
  border-radius: 12px;
  padding: 26px 24px;
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.plane-front .mini {
  box-shadow: var(--shadow-lg);
}

.tilt {
  transform: rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg));
  transition: transform 300ms var(--ease);
}

@media (min-width: 1024px) {
  .hero-grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 6fr);
  }
  /* Two lines: "Show the system," then the italic phrase. */
  .hero h1 {
    font-size: clamp(2.6rem, 1.2rem + 3.4vw, 4.5rem);
  }
  .hero h1 em {
    display: block;
  }
  .actions {
    flex-direction: row;
    flex-wrap: wrap;
  }
  .fan-clip {
    overflow: visible;
    margin-inline: 0 calc(-1 * var(--gutter));
  }
  .fan {
    --rm: 1;
    --cs: 1;
    height: 600px;
  }
  .plane-back {
    --ox: clamp(-120px, -8vw + 10px, -80px);
    --oy: -64px;
  }
  .plane-mid {
    --ox: 10px;
    --oy: -10px;
  }
  .plane-front {
    --ox: clamp(80px, 9vw - 20px, 140px);
    --oy: 56px;
  }
}

/* Narrow desktops: a smaller fan so the front card stays in the viewport. */
@media (min-width: 1024px) and (max-width: 1199px) {
  .fan {
    --cs: 0.88;
    height: 540px;
    /* The back card has room to spare; the front card's shadow needs it. */
    left: -48px;
  }
}

@media (min-width: 1200px) and (max-width: 1299px) {
  .fan {
    left: -32px;
  }
}

@media (max-width: 1023px) {
  .hero .btn-lg {
    width: 100%;
  }
}

/* ---------- Problem ---------- */

.split {
  display: grid;
  gap: 48px;
  align-items: center;
}

.contrast {
  display: grid;
  gap: 16px;
}

.tiles {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 14px;
}

.tiles li {
  font-size: 0.875rem;
  color: var(--muted);
}

.hatch {
  display: block;
  aspect-ratio: 4 / 3;
  margin-bottom: 6px;
  border-radius: 6px;
  background-color: var(--sunken);
  background-image: repeating-linear-gradient(
    135deg,
    transparent 0 7px,
    var(--border) 7px 8px
  );
}

.contrast h3 {
  margin-top: 14px;
}

.mono-rows {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.mono-rows li {
  padding-block: 10px;
  border-top: 1px solid var(--border);
}

.mono-rows .sig {
  font-weight: 500;
}

@media (min-width: 900px) {
  .split {
    grid-template-columns: 1fr 1fr;
  }
  .contrast {
    grid-template-columns: 1fr 1fr;
    align-items: stretch;
  }
}

/* ---------- How it works ---------- */

.steps {
  display: grid;
  gap: 40px;
  margin-top: 56px;
}

.step {
  position: relative;
  padding-top: 24px;
}

.step::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: var(--border-strong);
  transform-origin: left;
}

.step-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 2.5rem;
  line-height: 1;
  color: var(--accent);
}

.icon {
  display: block;
  margin-block: 20px 16px;
  color: var(--muted);
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.icon-front {
  fill: var(--bg);
}

.icon-dot {
  fill: var(--accent);
  stroke: none;
}

.step p {
  margin-top: 8px;
  color: var(--muted);
  max-width: 36ch;
}

.center-note {
  margin-top: 56px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--muted);
}

@media (min-width: 860px) {
  .steps {
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
  }
}

/* ---------- Anatomy ---------- */

.anat {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 48px;
}

/* Below 1024px the card breaks apart: each step is followed by its block. */
.anat-card {
  display: contents;
}

.anat-head {
  order: 0;
}
.anat-step[data-step="scale"] {
  order: 1;
}
.block[data-block="scale"] {
  order: 2;
}
.anat-step[data-step="model"] {
  order: 3;
}
.block[data-block="model"] {
  order: 4;
}
.anat-step[data-step="tradeoffs"] {
  order: 5;
}
.block[data-block="tradeoffs"] {
  order: 6;
}
.anat-step[data-step="results"] {
  order: 7;
}
.block[data-block="results"] {
  order: 8;
}

.anat-step {
  padding-top: 24px;
}

.anat-step h3 {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 500;
  letter-spacing: -0.02em;
}

.anat-step .q {
  margin-top: 4px;
  font-family: var(--font-display);
  font-style: italic;
  font-size: 1.25rem;
  color: var(--accent);
}

.anat-step p:last-child {
  margin-top: 10px;
  color: var(--muted);
  max-width: 44ch;
}

.anat-title {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.anat-summary {
  margin-top: 8px;
  color: var(--muted);
}

.block {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  box-shadow: var(--shadow-sm);
  min-width: 0;
}

.block::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 16px;
  bottom: 16px;
  width: 3px;
  border-radius: 2px;
  background: var(--accent);
  opacity: 0;
  transform: translateX(-8px);
  transition:
    opacity 300ms var(--ease),
    transform 300ms var(--ease);
}

.block .label {
  transition: color 300ms var(--ease);
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.metric {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  padding: 6px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--sunken);
  color: var(--muted);
}

.metric b {
  color: var(--ink);
  font-weight: 500;
}

.code {
  margin-top: 12px;
  padding: 16px;
  background: var(--sunken);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.8125rem;
  line-height: 1.7;
  overflow-x: auto;
  max-width: 100%;
}

.ln {
  display: inline-block;
}

.cm {
  color: var(--muted);
}

.trade {
  display: grid;
  gap: 6px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}

.trade:first-of-type {
  border-top: 0;
  padding-top: 0;
}

.trade div {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 12px;
  font-size: 0.9375rem;
}

.trade dt {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: var(--muted);
  padding-top: 4px;
}

.result {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: 4px 16px;
  margin-top: 12px;
  font-family: var(--font-mono);
}

.result-label {
  font-size: 0.8125rem;
  color: var(--muted);
}

.result-vals {
  font-size: clamp(1.25rem, 1rem + 1vw, 1.625rem);
  font-weight: 500;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

.center-link {
  margin-top: 48px;
  text-align: center;
}

/* At 1024px and up the card pins beside the steps, unless main.js marks the
   viewport too short for it (.is-unpinned): then the mobile layout stays. */
@media (min-width: 1024px) {
  .anat:not(.is-unpinned) {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 560px;
    column-gap: 64px;
    gap: 0 64px;
  }
  .anat:not(.is-unpinned) .anat-step {
    grid-column: 1;
    min-height: 80vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 0;
    transition: opacity 300ms var(--ease);
  }
  .anat:not(.is-unpinned) .anat-card {
    display: block;
    grid-column: 2;
    grid-row: 1 / span 4;
    align-self: start;
    position: sticky;
    top: 96px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 14px;
    box-shadow: var(--shadow-md);
    padding: 28px;
    margin-block: 10vh 0;
  }
  .anat:not(.is-unpinned) .anat-card .block {
    border: 0;
    border-radius: 0;
    box-shadow: none;
    background: transparent;
    padding: 14px 0 14px 20px;
    border-top: 1px solid var(--border);
    margin-left: -20px;
    transition: opacity 300ms var(--ease);
  }
  .anat:not(.is-unpinned) .anat-card .anat-head {
    padding-bottom: 12px;
  }
  /* Compact enough that the whole card fits under the sticky top. */
  .anat:not(.is-unpinned) .anat-card {
    padding: 22px 26px;
  }
  .anat:not(.is-unpinned) .anat-card .anat-title {
    font-size: 1.5rem;
  }
  .anat:not(.is-unpinned) .anat-card .anat-summary {
    margin-top: 4px;
    font-size: 0.9375rem;
    line-height: 1.5;
  }
  .anat:not(.is-unpinned) .anat-card .block {
    padding-block: 10px;
  }
  .anat:not(.is-unpinned) .anat-card .chips,
  .anat:not(.is-unpinned) .anat-card .code {
    margin-top: 8px;
  }
  .anat:not(.is-unpinned) .anat-card .metric {
    padding: 4px 10px;
    font-size: 0.75rem;
  }
  .anat:not(.is-unpinned) .anat-card .code {
    padding: 10px 14px;
    font-size: 0.75rem;
    line-height: 1.6;
  }
  .anat:not(.is-unpinned) .anat-card .trade {
    grid-template-columns: 1fr 1fr;
    gap: 2px 16px;
    margin-top: 8px;
    padding-top: 8px;
  }
  .anat:not(.is-unpinned) .anat-card .trade div {
    grid-template-columns: 1fr;
    gap: 0;
    font-size: 0.875rem;
    line-height: 1.45;
  }
  .anat:not(.is-unpinned) .anat-card .trade div:last-child {
    grid-column: 1 / -1;
  }
  .anat:not(.is-unpinned) .anat-card .trade dt {
    padding-top: 0;
  }
  .anat:not(.is-unpinned) .anat-card .result {
    margin-top: 6px;
  }
  .anat:not(.is-unpinned) .anat-card .result-vals {
    font-size: 1.375rem;
  }
  .anat:not(.is-unpinned) .anat-card .block::before {
    left: 0;
    top: 14px;
    bottom: 14px;
  }
  /* The section is roughly 330vh: four 80vh steps plus the heading, and a
     10vh tail so the card stays pinned while the last step is centred. */
  .anat:not(.is-unpinned)::after {
    content: "";
    grid-column: 1;
    order: 9;
    height: 10vh;
  }

  /* Active state, driven by main.js. */
  .anat:not(.is-unpinned)[data-active] .anat-step:not(.is-active) {
    opacity: 0.45;
  }
  .anat:not(.is-unpinned)[data-active] .block:not(.is-active) {
    opacity: 0.4;
  }
  .anat:not(.is-unpinned) .block.is-active .label {
    color: var(--accent);
  }
  .anat:not(.is-unpinned) .block.is-active::before {
    opacity: 1;
    transform: none;
  }
  html.js .anat:not(.is-unpinned) .anat-card:not(.typed) .ln {
    opacity: 0;
    transform: translateX(-4px);
  }
  html.js .anat:not(.is-unpinned) .anat-card .ln {
    transition:
      opacity 200ms var(--ease),
      transform 200ms var(--ease);
  }
  .anat:not(.is-unpinned) .anat-card .ln:nth-child(2) {
    transition-delay: 90ms;
  }
  .anat:not(.is-unpinned) .anat-card .ln:nth-child(3) {
    transition-delay: 180ms;
  }
  .anat:not(.is-unpinned) .anat-card .ln:nth-child(4) {
    transition-delay: 270ms;
  }
  .anat:not(.is-unpinned) .anat-card .ln:nth-child(5) {
    transition-delay: 360ms;
  }
}

/* A wider card wraps less, so it stays short enough to pin on ~900px screens. */
@media (min-width: 1280px) {
  .anat:not(.is-unpinned) {
    grid-template-columns: minmax(0, 1fr) 640px;
  }
}

/* ---------- Impact ---------- */

.impact-grid {
  display: grid;
  gap: 32px;
  margin-top: 48px;
  align-items: start;
}

.demo .label {
  display: block;
}

.input {
  display: block;
  width: 100%;
  min-height: 48px;
  margin-top: 10px;
  padding: 10px 14px;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  background: var(--bg);
  color: var(--ink);
  font: inherit;
  font-size: 1rem;
  transition: border-color 150ms var(--ease);
}

.input:hover {
  border-color: var(--muted);
}

.input:focus-visible {
  border-color: var(--accent);
}

.feedback {
  margin-top: 12px;
  min-height: 32px;
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 5px 12px;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 500;
}

.pill-warn {
  background: var(--warn-soft);
  color: var(--warn);
}

.pill-ok {
  background: var(--signal-soft);
  color: var(--signal);
}

.suggest {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

.chip-btn {
  min-height: 44px;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--sunken);
  color: var(--ink);
  font: inherit;
  font-size: 0.9375rem;
  text-align: left;
  cursor: pointer;
  transition:
    border-color 150ms var(--ease),
    background-color 150ms var(--ease),
    transform 120ms var(--ease);
}

.chip-btn:hover {
  border-color: var(--accent);
  background-color: var(--accent-soft);
}

.tl {
  position: relative;
  padding-left: 28px;
}

.tl::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--border-strong);
}

.tl li {
  position: relative;
  padding-bottom: 28px;
}

.tl li::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 7px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--bg);
  transition: transform 500ms var(--spring);
}

.tl li:nth-child(2)::before {
  transition-delay: 100ms;
}

.tl li:nth-child(3)::before {
  transition-delay: 200ms;
}

html.js .timeline-wrap:not(.is-in) .tl li::before {
  transform: scale(0);
}

.role,
.range {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
}

.role b {
  font-weight: 500;
  color: var(--ink);
}

.range,
.dur,
.caption {
  color: var(--muted);
}

.tl li p:last-child {
  margin-top: 6px;
  max-width: 52ch;
}

.num {
  color: var(--signal);
  font-weight: 600;
}

.caption {
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

@media (min-width: 900px) {
  .impact-grid {
    grid-template-columns: 1fr 1fr;
    gap: 56px;
  }
}

/* ---------- Stack ---------- */

.stack-table {
  width: 100%;
  margin-top: 48px;
  border-collapse: separate;
  border-spacing: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.stack-table th,
.stack-table td {
  padding: 14px 18px;
  text-align: left;
  vertical-align: middle;
  border-top: 1px solid var(--border);
}

.stack-table thead th,
.stack-table thead td {
  border-top: 0;
  background: var(--sunken);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.stack-table tbody th {
  width: 22%;
  font-weight: 500;
  font-size: 0.9375rem;
}

.chip {
  display: inline-flex;
  align-items: baseline;
  gap: 4px;
  padding: 5px 12px;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  transition: opacity 300ms var(--ease);
}

.chip small {
  font-size: 0.6875rem;
  color: var(--muted);
}

.chip.core {
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid transparent;
}

.chip.prod {
  border: 1px solid var(--border-strong);
  color: var(--ink);
}

.chip.fam {
  border: 1px dashed var(--border-strong);
  color: var(--muted);
}

html.js .stack-table:not(.is-in) .chip {
  opacity: 0;
}

.stack-table tbody tr:nth-child(2) .chip {
  transition-delay: 60ms;
}
.stack-table tbody tr:nth-child(3) .chip {
  transition-delay: 120ms;
}
.stack-table tbody tr:nth-child(4) .chip {
  transition-delay: 180ms;
}
.stack-table tbody tr:nth-child(5) .chip {
  transition-delay: 240ms;
}
.stack-table tbody tr:nth-child(6) .chip {
  transition-delay: 300ms;
}

@media (max-width: 719px) {
  .stack-table,
  .stack-table tbody,
  .stack-table tr,
  .stack-table th,
  .stack-table td {
    display: block;
  }
  .stack-table thead {
    display: none;
  }
  .stack-table tbody tr {
    padding: 16px 18px;
    border-top: 1px solid var(--border);
  }
  .stack-table tbody tr:first-child {
    border-top: 0;
  }
  .stack-table tbody th,
  .stack-table td {
    width: auto;
    padding: 0;
    border: 0;
  }
  .stack-table tbody th {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 8px;
  }
  .stack-table td {
    display: flex;
    align-items: center;
    gap: 12px;
    padding-block: 4px;
  }
  .stack-table td::before {
    content: attr(data-level);
    width: 92px;
    flex: none;
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--muted);
  }
  .stack-table td:empty {
    display: none;
  }
}

/* ---------- Themes ---------- */

.seg {
  display: none;
  margin-top: 40px;
  padding: 4px;
  gap: 4px;
  background: var(--sunken);
  border: 1px solid var(--border);
  border-radius: 10px;
}

html.js .seg {
  display: inline-flex;
}

.seg button {
  min-height: 44px;
  min-width: 112px;
  padding: 0 16px;
  border: 1px solid transparent;
  border-radius: 7px;
  background: transparent;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  cursor: pointer;
  transition:
    background-color 150ms var(--ease),
    color 150ms var(--ease),
    border-color 150ms var(--ease),
    transform 120ms var(--ease);
}

.seg button:hover {
  color: var(--ink);
}

.seg button[aria-pressed="true"] {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--border);
  box-shadow: var(--shadow-sm);
}

.seg-desc {
  display: none;
  margin-top: 12px;
  font-size: 0.9375rem;
  color: var(--muted);
}

html.js .seg-desc {
  display: block;
}

.frames {
  display: grid;
  gap: 32px;
  margin-top: 24px;
}

.frame-caption {
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 0.9375rem;
}

.frame-caption b {
  color: var(--ink);
  font-weight: 600;
}

html.js .frame-caption {
  display: none;
}

.window {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.chrome {
  display: flex;
  align-items: center;
  gap: 6px;
  height: 40px;
  padding: 0 14px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

.chrome i {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--border-strong);
}

.url {
  margin-left: 12px;
  padding: 3px 12px;
  border-radius: 6px;
  background: var(--sunken);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.export {
  height: 520px;
  overflow-y: auto;
  border: 0;
  padding: 36px clamp(20px, 5vw, 56px);
}

.ex-name {
  font-size: clamp(1.75rem, 1.4rem + 1.5vw, 2.5rem);
}

.ex-headline {
  margin-top: 4px;
  font-size: 1.0625rem;
}

.ex-meta {
  margin-top: 6px;
  font-size: 0.875rem;
  color: var(--t-muted);
}

.ex-link {
  color: var(--t-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.ex-nav {
  margin-top: 20px;
}

.ex-section {
  margin-top: 28px;
}

.ex-sec-title {
  margin-top: 4px;
  font-family: var(--t-heading);
  font-size: 1.375rem;
  font-weight: 600;
}

.ex-body {
  margin-top: 8px;
  max-width: 62ch;
  font-size: 0.9375rem;
  line-height: 1.6;
}

.ex-card {
  margin-top: 12px;
  padding: 20px;
  border: 1px solid var(--t-border);
  border-radius: 6px;
  background: var(--t-surface);
}

.ex-card .mini-title {
  margin-top: 0;
  font-size: 1.125rem;
}

.th[data-theme="blueprint"] .ex-card {
  border-radius: 0;
}

/* With JS, one frame switches theme; the other two are removed. */
html.js .frame + .frame {
  display: none;
}

@media (max-width: 719px) {
  html.js .seg {
    display: flex;
  }
  .seg button {
    flex: 1;
    min-width: 0;
  }
  .export {
    height: 440px;
  }
}

/* ---------- App frame ---------- */

.device {
  margin-top: 48px;
  box-shadow: var(--shadow-lg);
}

.device iframe {
  display: block;
  width: 100%;
  height: min(80vh, 760px);
  border: 0;
  background: var(--bg);
}

.under-frame {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 8px 24px;
  margin-top: 16px;
}

.tip {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--muted);
}

@media (max-width: 719px) {
  .device iframe {
    height: 640px;
  }
  .device .url {
    display: none;
  }
}

/* ---------- Ownership ---------- */

.facts {
  display: grid;
  gap: 16px;
  margin-top: 48px;
}

.fact {
  transition:
    transform 200ms var(--ease),
    border-color 200ms var(--ease),
    opacity 500ms var(--ease);
}

.fact h3 {
  margin-top: 12px;
}

.fact p:last-child {
  margin-top: 6px;
  color: var(--muted);
}

.fact code {
  font-size: 0.875em;
  color: var(--ink);
}

@media (min-width: 720px) {
  .facts {
    grid-template-columns: 1fr 1fr;
  }
}

@media (hover: hover) and (pointer: fine) {
  .fact.is-in:hover,
  html:not(.js) .fact:hover {
    transform: translateY(-2px);
    border-color: var(--border-strong);
  }
}

/* ---------- Closing CTA ---------- */

.closing {
  position: relative;
  overflow: hidden;
  padding-block: clamp(96px, 12vw, 168px);
  background-color: #111215;
  background-image: linear-gradient(rgb(233 233 230 / 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgb(233 233 230 / 0.04) 1px, transparent 1px);
  background-size: 24px 24px;
  color: #e9e9e6;
}

.closing-inner {
  position: relative;
  z-index: 1;
}

.closing .eyebrow,
.closing .fine,
.closing-line {
  color: #a3a6ae;
}

.closing h2 {
  font-size: calc(var(--h1) * 0.8);
  line-height: 1.08;
  max-width: 18ch;
}

.closing h2 em {
  color: #9aa5ff;
}

.closing-line {
  margin-top: 20px;
  max-width: 52ch;
  font-size: 1.125rem;
}

.btn-closing {
  margin-top: 32px;
  background: #9aa5ff;
  color: #121433;
}

.btn-closing:hover {
  background: #b4bcff;
}

.closing a:focus-visible {
  outline-color: #9aa5ff;
}

.bus {
  position: absolute;
  inset: 12% 0;
}

.bus-lines {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.bus-lines line {
  stroke: #e9e9e6;
  stroke-opacity: 0.08;
  stroke-width: 1;
  vector-effect: non-scaling-stroke;
}

.bus i {
  position: absolute;
  left: 0;
  right: 0;
  top: var(--y);
  height: 0;
  animation: travel var(--dur) linear infinite;
  animation-delay: calc(var(--dur) * -0.37);
}

.bus i::after {
  content: "";
  position: absolute;
  left: -4px;
  top: -3px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #9aa5ff;
  box-shadow: 0 0 10px rgb(154 165 255 / 0.7);
}

@keyframes travel {
  from {
    transform: translateX(-2%);
  }
  to {
    transform: translateX(102%);
  }
}

@media (max-width: 1023px) {
  .btn-closing {
    width: 100%;
  }
}

/* ---------- Footer ---------- */

.footer {
  border-top: 1px solid var(--border);
  padding-block: 48px 32px;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.tagline {
  color: var(--muted);
  font-size: 0.9375rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 8px;
}

.footer-links a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 10px;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--muted);
  text-decoration: none;
  transition:
    color 150ms var(--ease),
    background-color 150ms var(--ease);
}

.footer-links a:hover {
  color: var(--accent);
  background-color: var(--sunken);
}

.footer-note {
  margin-top: 28px;
  font-size: 0.875rem;
  color: var(--muted);
}

/* ---------- Reveal (only with JS) ---------- */

html.js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition:
    opacity 500ms var(--ease) var(--d, 0ms),
    transform 500ms var(--ease) var(--d, 0ms);
}

html.js [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

html.js .step::before {
  transform: scaleX(0);
  transition: transform 700ms var(--ease) calc(var(--d, 0ms) + 100ms);
}

html.js .step.is-in::before {
  transform: scaleX(1);
}

@media (min-width: 1024px) {
  /* The sticky card's blocks dim instead of fading up. */
  html.js .anat:not(.is-unpinned) .anat-card [data-reveal] {
    opacity: 1;
    transform: none;
    transition: opacity 300ms var(--ease);
  }
  .anat:not(.is-unpinned)[data-active] .anat-card .block:not(.is-active) {
    opacity: 0.4;
  }
  html.js .anat:not(.is-unpinned) .anat-step[data-reveal].is-in {
    transition: opacity 300ms var(--ease);
  }
}

/* ---------- Reduced motion: everything in its final state ---------- */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation: none !important;
    transition-duration: 0ms !important;
    transition-delay: 0ms !important;
  }
  html.js [data-reveal],
  html.js .step::before,
  html.js .anat-card .ln,
  html.js .timeline-wrap .tl li::before,
  html.js .stack-table .chip {
    opacity: 1 !important;
    transform: none !important;
  }
  .anat[data-active] .anat-step,
  .anat[data-active] .block {
    opacity: 1 !important;
  }
  .plane {
    --p: 0 !important;
  }
  .tilt {
    transform: none;
  }
  .bus i {
    transform: translateX(var(--rest));
  }
  a:active,
  button:active {
    transform: none;
  }
}