:root {
  --cyan: #3a8a9a;
  --cyan-deep: #1c3d48;
  --bath: #4a7ec4;
  --bubble: #e8f4ff;
  --ink: #e8f0f2;
  --mute: #8aa8b0;
  --warn: #d07030;
  --ok: #3a8a9a;
  --line: rgba(58, 138, 154, 0.22);
  --shadow: 0 22px 48px rgba(28, 61, 72, 0.35);
  --serif: "Noto Serif SC", "Songti SC", serif;
  --sans: "Noto Sans SC", "PingFang SC", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, Menlo, monospace;
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
section[id] { scroll-margin-top: 76px; }
body { margin: 0; color: var(--ink); background: #15262c; font-family: var(--sans); font-size: 16px; line-height: 1.75; }
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.app-link { color: #8fd4e0; text-decoration: underline; text-underline-offset: 3px; }
button { font-family: inherit; cursor: pointer; }
code { font-family: var(--mono); font-size: 0.92em; background: rgba(58, 138, 154, 0.15); padding: 0.05em 0.35em; }
.grain { pointer-events: none; position: fixed; inset: 0; z-index: 40; opacity: 0.12; background-image: url("images/texture.webp"); background-size: 640px auto; mix-blend-mode: overlay; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 12px; top: 12px; z-index: 60; background: var(--cyan); color: #15262c; padding: 8px 12px; }
.nav { position: sticky; top: 0; z-index: 30; display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 12px 28px; background: rgba(21, 38, 44, 0.9); backdrop-filter: blur(12px); border-bottom: 1px solid var(--line); }
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--serif); font-weight: 700; }
.brand small { display: block; font-family: var(--mono); font-weight: 400; font-size: 10px; letter-spacing: 0.14em; color: var(--mute); }
.seal { width: 36px; height: 36px; display: grid; place-items: center; border: 1px solid var(--cyan); color: var(--cyan); font-family: var(--serif); }
.nav-toggle { display: none; background: transparent; border: 1px solid var(--cyan); color: var(--cyan); padding: 6px 12px; }
.nav-links { display: flex; gap: 18px; font-size: 14px; }
.nav-links a { color: var(--mute); border-bottom: 1px solid transparent; padding-bottom: 2px; }
.nav-links a.is-active, .nav-links a:hover { color: #8fd4e0; border-bottom-color: var(--bath); }
.nav-links .live { color: #15262c; background: var(--cyan); border: 0; padding: 6px 12px; }
.hero { position: relative; min-height: 94vh; display: grid; align-items: end; overflow: hidden; }
.hero img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.hero::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, rgba(21, 38, 44, 0.15) 0%, rgba(21, 38, 44, 0.5) 48%, rgba(21, 38, 44, 0.94) 100%); }
.hero-inner { position: relative; z-index: 1; padding: 8vh 8vw 9vh; max-width: 900px; }
.kicker, .vlabel { font-family: var(--mono); letter-spacing: 0.2em; font-size: 12px; color: #8fd4e0; margin: 0 0 12px; }
h1, h2, h3 { font-family: var(--serif); font-weight: 700; line-height: 0.98; margin: 0 0 16px; letter-spacing: -0.03em; }
h1 { font-size: clamp(48px, 8.5vw, 96px); }
h2 { font-size: clamp(28px, 4vw, 44px); line-height: 1.15; }
h3 { font-size: 22px; line-height: 1.25; }
.lead { font-size: 18px; max-width: 42em; color: rgba(232, 240, 242, 0.9); }
.meta-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 22px 0; }
.chip { border: 1px solid rgba(143, 212, 224, 0.4); padding: 4px 10px; font-size: 12px; font-family: var(--mono); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 10px 18px; border: 1px solid currentColor; font-size: 14px; }
.btn-fill { background: var(--cyan); color: #15262c; border-color: var(--cyan); }
.btn-ghost { background: transparent; color: inherit; }
.wrap { width: min(1120px, calc(100% - 48px)); margin: 0 auto; padding: 88px 0; }
.section-head { display: grid; grid-template-columns: 150px 1fr; gap: 24px; margin-bottom: 40px; }
.section-head p:last-child { color: var(--mute); margin: 0; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.card { background: rgba(28, 61, 72, 0.55); border: 1px solid var(--line); padding: 22px; min-height: 220px; }
.stamp { display: inline-block; font-size: 11px; letter-spacing: 0.16em; color: #8fd4e0; border: 1px solid var(--cyan); padding: 2px 8px; margin-bottom: 10px; font-family: var(--mono); }
.card ul, .io-grid ul, .rule-list { margin: 0; padding-left: 1.1em; }
.card li, .io-grid li, .rule-list li { margin: 0.35em 0; }
.alt { background: linear-gradient(180deg, #1c3d48 0%, #15262c 100%); }
.step { display: grid; grid-template-columns: 1fr 1fr; gap: 36px; align-items: center; margin-bottom: 72px; }
.step.reverse { direction: rtl; }
.step.reverse > * { direction: ltr; }
.num { font-family: var(--mono); font-size: 13px; letter-spacing: 0.2em; color: #8fd4e0; display: block; margin-bottom: 8px; }
figure { margin: 0; }
figure img { width: 100%; height: 320px; object-fit: cover; box-shadow: var(--shadow); }
figcaption { margin-top: 10px; font-size: 13px; color: var(--mute); font-style: italic; }
.gauge-demo { margin-top: 22px; padding: 16px; border: 1px dashed var(--cyan); background: rgba(58, 138, 154, 0.08); }
.clock-label { margin: 0 0 12px; font-size: 12px; letter-spacing: 0.08em; color: var(--mute); font-family: var(--mono); }
.slider { display: grid; grid-template-columns: 50px 1fr 56px; gap: 10px; align-items: center; font-size: 13px; color: var(--mute); }
.slider input { width: 100%; accent-color: var(--bath); }
.slider span { font-family: var(--mono); color: #8fd4e0; }
.tri-state { margin: 12px 0 0; font-family: var(--mono); font-size: 13px; }
.tri-state.warn { color: var(--warn); }
.tri-state.ok { color: #8fd4e0; }
.bench-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.bench { padding: 18px; background: #1c3d48; border: 1px solid var(--line); }
.bench h3 { font-size: 18px; margin-bottom: 8px; }
.bench p { margin: 0; color: var(--mute); font-size: 14px; }
.rule-list { font-size: 17px; max-width: 46em; }
.rule-list li { border-left: 2px solid var(--cyan); padding: 8px 0 8px 14px; }
.io-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
footer { border-top: 1px solid var(--line); background: #0e1a1e; color: var(--mute); }
.footer-inner { padding: 32px 0; display: flex; justify-content: space-between; gap: 16px; font-size: 13px; }
@media (max-width: 860px) {
  .nav-toggle { display: block; }
  .nav-links { display: none; position: absolute; top: 100%; left: 0; right: 0; flex-direction: column; padding: 12px 20px 18px; background: #15262c; border-bottom: 1px solid var(--line); }
  .nav-links.open { display: flex; }
  .section-head, .grid-3, .step, .step.reverse, .io-grid, .bench-grid { grid-template-columns: 1fr; direction: ltr; display: grid; }
  .footer-inner { display: flex; flex-direction: column; }
  h1 { font-size: 44px; }
  figure img { height: 220px; }
  .wrap { width: min(1120px, calc(100% - 32px)); padding: 56px 0; }
  .slider { grid-template-columns: 1fr; }
}