:root {
  --snow: #f3efe6;
  --paper: #fffdf8;
  --steel: #3d4650;
  --ink: #1a1c1e;
  --mute: #6b737c;
  --yellow: #d4a017;
  --warn: #b42318;
  --ok: #3d6b4f;
  --line: rgba(61, 70, 80, 0.16);
  --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: 72px; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--snow);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
}
body::before {
  content: "";
  position: fixed;
  left: 0; top: 0; bottom: 0;
  width: 10px;
  background: repeating-linear-gradient(-45deg, var(--yellow), var(--yellow) 8px, #1a1c1e 8px, #1a1c1e 16px);
  z-index: 50;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.app-link { color: #8a6a10; text-decoration: underline; text-underline-offset: 3px; }
button { font-family: inherit; cursor: pointer; }
code { font-family: var(--mono); font-size: 0.92em; background: rgba(212, 160, 23, 0.18); padding: 0.05em 0.35em; }
.grain {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 40;
  opacity: 0.08;
  background-image: url("images/texture.webp");
  background-size: 480px auto;
  mix-blend-mode: multiply;
}
.skip { position: absolute; left: -999px; }
.skip:focus { left: 20px; top: 12px; z-index: 60; background: var(--yellow); color: var(--ink); 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 12px 36px;
  background: rgba(243, 239, 230, 0.92);
  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: 0.16em; color: var(--mute); }
.seal {
  width: 36px; height: 36px; display: grid; place-items: center;
  background: var(--steel); color: var(--snow); font-family: var(--serif);
}
.nav-toggle { display: none; background: transparent; border: 1px solid var(--steel); color: var(--steel); padding: 6px 12px; }
.nav-links { display: flex; gap: 16px; font-size: 14px; }
.nav-links a { color: var(--mute); }
.nav-links a.is-active, .nav-links a:hover { color: var(--ink); border-bottom: 1px solid var(--yellow); }
.nav-links .live { color: var(--ink); background: var(--yellow); padding: 6px 12px; border: 0; }
.hero {
  position: relative;
  min-height: 94vh;
  display: grid;
  align-items: end;
  overflow: hidden;
  color: var(--snow);
}
.hero-visual { position: absolute; inset: 0; }
.hero-visual img { width: 100%; height: 100%; object-fit: cover; }
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(26, 28, 30, 0.15) 0%, rgba(26, 28, 30, 0.45) 42%, rgba(26, 28, 30, 0.88) 100%);
}
.hero-inner { position: relative; z-index: 1; padding: 8vh 8vw 9vh 48px; max-width: 880px; }
.hero h1 { color: var(--snow); }
.hero .lead { color: rgba(243, 239, 230, 0.92); }
.hero .chip { background: transparent; color: var(--snow); border-color: rgba(243, 239, 230, 0.4); }
.hero .btn-ghost { color: var(--snow); }
.kicker, .vlabel { font-family: var(--mono); letter-spacing: 0.18em; font-size: 12px; color: #8a6a10; margin: 0 0 12px; }
.hero .kicker { color: var(--yellow); }
h1, h2, h3 { font-family: var(--serif); font-weight: 700; line-height: 1.02; margin: 0 0 16px; letter-spacing: -0.03em; }
h1 { font-size: clamp(40px, 6vw, 78px); }
h2 { font-size: clamp(26px, 3.4vw, 40px); line-height: 1.18; }
h3 { font-size: 22px; line-height: 1.28; }
.lead { font-size: 17px; max-width: 40em; color: var(--steel); }
.meta-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 22px 0; }
.chip { border: 1px solid var(--line); padding: 4px 10px; font-size: 12px; font-family: var(--mono); background: var(--snow); }
.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(--yellow); color: var(--ink); border-color: var(--yellow); }
.btn-ghost { background: transparent; color: var(--steel); }
.wrap { width: min(1120px, calc(100% - 64px)); margin: 0 auto; padding: 84px 0; }
.section-head { display: grid; grid-template-columns: 140px 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: var(--paper); border: 1px solid var(--line); padding: 22px; min-height: 210px; box-shadow: 0 18px 40px rgba(26, 28, 30, 0.06); }
.stamp { display: inline-block; font-size: 11px; letter-spacing: 0.16em; color: #8a6a10; border: 1px solid var(--yellow); 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, #e7e1d4 0%, var(--snow) 100%); }
.step { display: grid; grid-template-columns: 1fr 1fr; gap: 36px; align-items: center; margin-bottom: 68px; }
.step.reverse { direction: rtl; }
.step.reverse > * { direction: ltr; }
.num { font-family: var(--mono); font-size: 13px; letter-spacing: 0.2em; color: #8a6a10; display: block; margin-bottom: 8px; }
figure { margin: 0; }
figure img { width: 100%; height: 320px; object-fit: cover; border: 1px solid var(--line); }
figcaption { margin-top: 10px; font-size: 13px; color: var(--mute); font-style: italic; }
.gauge-demo { margin-top: 22px; padding: 16px; border: 1px dashed var(--yellow); background: rgba(212, 160, 23, 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: 72px 1fr 72px; gap: 10px; align-items: center; font-size: 13px; color: var(--mute); }
.slider input { width: 100%; accent-color: var(--yellow); }
.slider span { font-family: var(--mono); color: #8a6a10; }
.tri-state { margin: 12px 0 0; font-family: var(--mono); font-size: 13px; }
.tri-state.warn { color: var(--warn); }
.tri-state.ok { color: var(--ok); }
.bench-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.bench { padding: 18px; background: var(--paper); border-left: 4px solid var(--yellow); }
.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; }
.io-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; }
footer { padding: 28px 48px 48px; font-size: 13px; color: var(--mute); border-top: 1px solid var(--line); }
@media (max-width: 900px) {
  body::before { width: 6px; }
  .nav { padding-left: 20px; }
  .nav-toggle { display: inline-block; }
  .nav-links {
    display: none; position: absolute; top: 100%; left: 0; right: 0;
    flex-direction: column; background: var(--paper); padding: 16px 24px 24px;
    border-bottom: 1px solid var(--line);
  }
  .nav-links.open { display: flex; }
  .hero, .step, .step.reverse, .section-head, .grid-3, .bench-grid, .io-grid {
    grid-template-columns: 1fr;
    direction: ltr;
  }
  .hero-inner { padding: 18vh 24px 56px 28px; }
  .wrap { width: calc(100% - 36px); padding: 56px 0; }
}