:root {
  --bg: #030a14;
  --bg-2: #061527;
  --ink: #e6f1fb;
  --ink-2: #9db4c9;
  --ink-3: #6b8399;
  --cyan: #5fe1ff;
  --teal: #29c4b8;
  --coral: #ff7a59;
  --line: rgba(157, 180, 201, 0.16);
  --card: rgba(12, 32, 56, 0.55);
  --serif: "Fraunces", Georgia, serif;
  --sans: "Inter", system-ui, -apple-system, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: var(--cyan); text-decoration: none; }
a:hover { text-decoration: underline; }
b { font-weight: 600; color: #fff; }
em { font-style: normal; color: var(--cyan); }

/* ---------------------------------------------------------------- nav */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 20;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 28px;
  background: linear-gradient(to bottom, rgba(3, 10, 20, 0.85), rgba(3, 10, 20, 0));
  backdrop-filter: blur(6px);
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); font: 600 18px var(--serif); letter-spacing: 0.01em; }
.brand svg { width: 26px; fill: var(--cyan); }
.brand:hover { text-decoration: none; }
.links { display: flex; gap: 22px; align-items: center; }
.links a { color: var(--ink-2); font-size: 14px; }
.links a:hover { color: #fff; text-decoration: none; }
.links .gh { display: flex; gap: 7px; align-items: center; color: var(--ink); border: 1px solid var(--line); padding: 6px 12px; border-radius: 999px; }
.links .gh svg { width: 15px; fill: currentColor; }

/* ---------------------------------------------------------------- hero */
.hero { position: relative; min-height: 100vh; display: flex; align-items: flex-end; overflow: hidden; }
.hero-video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.hero-shade {
  position: absolute; inset: 0;
  background:
    linear-gradient(to top, var(--bg) 0%, rgba(3, 10, 20, 0.55) 38%, rgba(3, 10, 20, 0.05) 70%),
    linear-gradient(to right, rgba(3, 10, 20, 0.6), rgba(3, 10, 20, 0) 60%);
}
.hero-content { position: relative; max-width: 1180px; width: 100%; margin: 0 auto; padding: 0 28px 12vh; }
.kicker { font: 500 13px var(--mono); letter-spacing: 0.18em; text-transform: uppercase; color: var(--cyan); margin: 0 0 18px; }
h1 { font: 300 clamp(44px, 7.4vw, 96px)/1.02 var(--serif); letter-spacing: -0.02em; margin: 0 0 24px; }
.lede { max-width: 620px; font-size: clamp(17px, 1.6vw, 20px); color: #cfe0ee; margin: 0 0 32px; }
.cta { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 36px; }
.btn { display: inline-block; padding: 12px 22px; border-radius: 999px; border: 1px solid rgba(230, 241, 251, 0.35); color: var(--ink); font-weight: 500; font-size: 15px; }
.btn:hover { text-decoration: none; border-color: #fff; }
.btn.primary { background: var(--cyan); border-color: var(--cyan); color: #02121d; }
.btn.primary:hover { background: #8aeaff; }
.chips { list-style: none; padding: 0; margin: 0; display: flex; gap: 10px; flex-wrap: wrap; }
.chips li { font-size: 13px; color: var(--ink-2); padding: 7px 14px; border-radius: 999px; background: rgba(6, 21, 39, 0.6); border: 1px solid var(--line); backdrop-filter: blur(8px); }
.chips b { font-family: var(--mono); color: var(--cyan); font-weight: 600; margin-right: 4px; }
.scroll-hint { position: absolute; left: 50%; bottom: 26px; width: 22px; height: 36px; margin-left: -11px; border: 1.5px solid rgba(230, 241, 251, 0.45); border-radius: 12px; }
.scroll-hint span { position: absolute; left: 50%; top: 7px; width: 3px; height: 7px; margin-left: -1.5px; border-radius: 2px; background: var(--ink); animation: drip 1.8s infinite; }
@keyframes drip { 0% { opacity: 0; transform: translateY(0); } 30% { opacity: 1; } 100% { opacity: 0; transform: translateY(12px); } }

/* ---------------------------------------------------------------- sections */
.section { padding: 120px 0; position: relative; }
.section.alt { background: linear-gradient(180deg, var(--bg) 0%, var(--bg-2) 18%, var(--bg-2) 82%, var(--bg) 100%); }
.wrap { max-width: 1180px; margin: 0 auto; padding: 0 28px; }
.two { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.wrap.two + .wrap { margin-top: 56px; }
.eyebrow { font: 500 12px var(--mono); letter-spacing: 0.2em; text-transform: uppercase; color: var(--teal); margin: 0 0 14px; }
h2 { font: 300 clamp(32px, 4vw, 52px)/1.08 var(--serif); letter-spacing: -0.015em; margin: 0 0 24px; }
p { margin: 0 0 18px; color: #c4d6e6; }
.wide { max-width: 800px; }
.note { font-size: 14px; color: var(--ink-3); border-left: 2px solid var(--teal); padding-left: 14px; }
.caption { font-size: 13px; color: var(--ink-3); margin-top: 12px; }

.clip { margin: 0; }
.clip video { width: 100%; border-radius: 14px; display: block; box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5); }
.clip figcaption { font-size: 13px; color: var(--ink-3); margin-top: 10px; }

/* ---------------------------------------------------------------- demos */
.demo { position: relative; border-radius: 16px; overflow: hidden; border: 1px solid var(--line); background: #041220; }
.demo canvas { display: block; width: 100%; }
#school { height: 440px; cursor: crosshair; }
.demo-hud { position: absolute; left: 0; right: 0; bottom: 0; display: flex; justify-content: space-between; padding: 10px 14px; font: 12px var(--mono); color: var(--ink-2); background: linear-gradient(to top, rgba(3, 10, 20, 0.8), transparent); pointer-events: none; }
.demo-hud button { pointer-events: auto; }
#school-state { color: var(--cyan); }

.raymarch { display: grid; grid-template-columns: 1fr; }
#rm { aspect-ratio: 16 / 9; image-rendering: auto; }
.controls { padding: 16px 18px 6px; display: grid; grid-template-columns: 1fr 1fr; gap: 10px 18px; font-size: 14px; color: var(--ink-2); }
.controls label { display: flex; align-items: center; gap: 10px; }
.controls label:first-child { grid-column: 1 / -1; }
.controls input[type=range] { flex: 1; accent-color: var(--cyan); }
.controls output { font: 13px var(--mono); color: var(--cyan); min-width: 48px; text-align: right; }
.controls input[type=checkbox] { accent-color: var(--cyan); width: 16px; height: 16px; }
.controls .stat { grid-column: 1 / -1; font: 12px var(--mono); color: var(--ink-3); margin: 4px 0 8px; }

.facts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 64px; }
.facts div { padding: 22px; border-radius: 14px; background: var(--card); border: 1px solid var(--line); }
.facts b { display: block; font: 500 28px var(--serif); color: var(--cyan); margin-bottom: 6px; }
.facts span { font-size: 14px; color: var(--ink-2); }

/* ---------------------------------------------------------------- budget */
.budget { margin-top: 40px; }
.budget-toggle { display: inline-flex; border: 1px solid var(--line); border-radius: 999px; padding: 3px; margin-bottom: 18px; }
.budget-toggle button { font: 500 13px var(--sans); color: var(--ink-2); background: none; border: 0; padding: 7px 16px; border-radius: 999px; cursor: pointer; }
.budget-toggle button.on { background: var(--cyan); color: #02121d; }
.bar { display: flex; height: 64px; border-radius: 12px; overflow: hidden; background: #0a1f35; position: relative; }
.seg { height: 100%; position: relative; transition: flex-basis 0.6s cubic-bezier(.2, .7, .2, 1), filter 0.2s; cursor: pointer; border-right: 1px solid rgba(3, 10, 20, 0.6); display: flex; align-items: flex-end; padding: 0 6px 6px; overflow: hidden; }
.seg span { font: 11px var(--mono); color: rgba(2, 18, 29, 0.85); white-space: nowrap; }
.seg:hover, .seg.sel { filter: brightness(1.25); }
.scale { position: relative; height: 20px; font: 12px var(--mono); color: var(--ink-3); margin-top: 8px; }
.scale span { position: absolute; top: 0; white-space: nowrap; }
#budget-60 { color: var(--coral); transform: translateX(-2px); }
#budget-total { color: #fff; transform: translateX(-100%); }
.budget-detail { margin-top: 18px; padding: 18px 20px; border-radius: 12px; background: var(--card); border: 1px solid var(--line); min-height: 76px; color: var(--ink-2); font-size: 15px; }
.budget-detail b { font-family: var(--mono); }

/* ---------------------------------------------------------------- dvfs */
.dvfs-chart { height: 300px; position: relative; }
.dvfs-chart svg { width: 100%; height: 100%; overflow: visible; }

/* ---------------------------------------------------------------- energy */
.watts { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin: 40px 0 44px; }
.w { position: relative; padding: 22px 20px 26px; border-radius: 14px; background: var(--card); border: 1px solid var(--line); overflow: hidden; }
.w .n { font: 500 44px/1 var(--serif); color: #fff; }
.w .u { font: 16px var(--mono); color: var(--ink-3); margin-left: 6px; }
.w p { font-size: 14px; margin: 12px 0 0; color: var(--ink-2); }
.w small { color: var(--ink-3); }
.w i { position: absolute; left: 0; bottom: 0; height: 4px; width: 0; background: var(--teal); transition: width 1.4s cubic-bezier(.2, .7, .2, 1); }
.w.hot i { background: var(--coral); }
.w.hot .n { color: var(--coral); }
.states { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; margin-bottom: 28px; }
.state { padding: 14px 20px; border-radius: 12px; border: 1px solid var(--line); background: var(--card); }
.state b { display: block; font: 500 20px var(--serif); }
.state span { font: 12px var(--mono); color: var(--ink-3); }
.arrow { display: flex; flex-direction: column; font: 11px/1.4 var(--mono); color: var(--ink-3); gap: 6px; flex: 1 1 150px; min-width: 150px; max-width: 230px; }
.arrow span:first-child::after { content: " →"; color: var(--teal); }
.arrow span:last-child::before { content: "← "; color: var(--teal); }

/* ---------------------------------------------------------------- field */
#sdf { cursor: crosshair; aspect-ratio: 145 / 66; image-rendering: auto; }
.field.front #sdf { aspect-ratio: 145 / 70; }
button.link { background: none; border: 0; color: var(--cyan); font: 12px var(--mono); cursor: pointer; padding: 0; }

/* ---------------------------------------------------------------- tests */
.bugs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin: 40px 0 30px; }
.bug { padding: 22px; border-radius: 14px; background: var(--card); border: 1px solid var(--line); }
.bug b { display: block; font: 500 32px var(--serif); color: var(--coral); margin-bottom: 8px; }
.bug p { font-size: 14px; margin: 0; color: var(--ink-2); }
.cadences { display: flex; gap: 12px; flex-wrap: wrap; }
.cadences span { font: 13px var(--mono); color: var(--ink-2); padding: 8px 16px; border-radius: 999px; border: 1px solid var(--line); }
.cadences b { color: #7dffb2; margin-left: 6px; }

/* ---------------------------------------------------------------- gallery */
.gallery-section { padding: 0; }
.gallery { display: grid; grid-template-columns: 2fr 1fr 1fr; grid-template-rows: 280px 280px; gap: 6px; }
.gallery a:first-child { grid-row: 1 / 3; }
.gallery a:last-child { grid-column: 2 / 4; }
.gallery img { width: 100%; height: 100%; object-fit: cover; display: block; transition: transform 0.6s; }
.gallery a { overflow: hidden; display: block; }
.gallery a:hover img { transform: scale(1.03); }

/* ---------------------------------------------------------------- code */
.code { position: relative; }
.code pre { margin: 0; padding: 26px 24px; border-radius: 14px; background: #020811; border: 1px solid var(--line); font: 14px/1.8 var(--mono); color: #d7e8f5; overflow-x: auto; }
.code .c { color: var(--ink-3); }
.copy { position: absolute; top: 12px; right: 12px; font: 12px var(--mono); color: var(--ink-2); background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 5px 10px; cursor: pointer; }
.copy:hover { color: #fff; }

.footer { padding: 60px 28px 70px; text-align: center; border-top: 1px solid var(--line); }
.footer p { font-size: 14px; color: var(--ink-3); margin: 6px 0; }

/* ---------------------------------------------------------------- reveal */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity 0.6s, transform 0.6s cubic-bezier(.2, .7, .2, 1); }
.reveal.in { opacity: 1; transform: none; }

@media (max-width: 900px) {
  .links a:not(.gh) { display: none; }
  .two { grid-template-columns: 1fr; gap: 36px; }
  .facts, .watts, .bugs { grid-template-columns: 1fr 1fr; }
  .gallery { grid-template-columns: 1fr 1fr; grid-template-rows: 220px 160px 160px; }
  .gallery a:first-child { grid-column: 1 / 3; grid-row: auto; }
  .gallery a:last-child { grid-column: auto; }
  .section { padding: 84px 0; }
  #school { height: 360px; }
}
@media (max-width: 560px) {
  body { font-size: 16px; }
  .nav { padding: 12px 16px; }
  .wrap, .hero-content { padding-left: 16px; padding-right: 16px; }
  .facts, .watts, .bugs { grid-template-columns: 1fr; }
  .controls { grid-template-columns: 1fr; }
  .arrow { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .scroll-hint span { animation: none; }
}