:root {
  --oak: #3a2a18;
  --oak-2: #4a3824;
  --lane: #efe4c8;
  --oil: #c9a227;
  --thick: #1e1712;
  --mute: #7a6a50;
  --ink: #1e1712;
  --display: "IBM Plex Sans Condensed", "Noto Sans SC", sans-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: 78px; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--lane);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.app-link { color: #8a6810; text-decoration: underline; text-underline-offset: 3px; }
button { font-family: inherit; cursor: pointer; }
label { display: block; font-size: 13px; color: var(--mute); }
input[type="range"] { width: min(280px, 100%); accent-color: var(--oil); }
.oak {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 6;
  opacity: 0.12;
  background-image: url("images/texture.webp");
  background-size: 380px auto;
  mix-blend-mode: multiply;
}
.oil-river {
  position: sticky;
  top: 0;
  z-index: 45;
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  height: 10px;
  gap: 1px;
}
.oil-river i:nth-child(1) { background: #1e1712; }
.oil-river i:nth-child(2) { background: #2a240c; }
.oil-river i:nth-child(3) { background: #3d3410; }
.oil-river i:nth-child(4) { background: #5c4a12; }
.oil-river i:nth-child(5) { background: #8a7018; }
.oil-river i:nth-child(6) { background: #c9a227; }
.oil-river i:nth-child(7) { background: #d4c08a; }
.oil-river i:nth-child(8) { background: #eadcc8; }
.oil-river i:nth-child(9),
.oil-river i:nth-child(10),
.oil-river i:nth-child(11),
.oil-river i:nth-child(12) { background: #f4eee0; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 12px; top: 16px; z-index: 80; background: var(--oil); color: #111; padding: 8px; }
.bar {
  position: sticky;
  top: 10px;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 22px;
  background: var(--oak);
  color: var(--lane);
  border-bottom: 3px solid var(--oil);
}
.brand { font-family: var(--display); font-weight: 700; letter-spacing: 0.08em; }
.brand small {
  display: block;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: #c4b490;
  font-weight: 400;
}
.nav-toggle {
  display: none;
  background: var(--oil);
  color: #1e1712;
  border: 0;
  padding: 6px 12px;
  font-family: var(--display);
}
.nav-links { display: flex; gap: 14px; font-size: 14px; flex-wrap: wrap; }
.nav-links a { color: #c4b490; }
.nav-links a.is-active, .nav-links a:hover { color: var(--oil); }
.nav-links .live { background: var(--oil); color: #1e1712; padding: 6px 12px; }
.hero { padding-bottom: 48px; }
.lane { margin: 0; height: 42vh; overflow: hidden; }
.lane img { width: 100%; height: 100%; object-fit: cover; }
.copy { width: min(1040px, calc(100% - 40px)); margin: 0 auto; padding-top: 36px; }
.kicker {
  font-family: var(--mono);
  letter-spacing: 0.16em;
  font-size: 11px;
  color: #8a6810;
  margin: 0 0 12px;
}
h1, h2, h3 { font-family: var(--display); margin: 0 0 12px; line-height: 1.05; font-weight: 700; }
h1 { font-size: clamp(32px, 5vw, 56px); letter-spacing: 0.02em; }
h2 { font-size: clamp(24px, 3vw, 36px); }
.lead { max-width: 46em; color: var(--mute); }
.map {
  margin: 20px 0;
  padding: 16px 18px;
  background: #fff8ee;
  border: 1px solid #d4c08a;
  max-width: 36em;
}
.map.is-ok { border-color: #2f6b45; }
.heat {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 2px;
  margin-bottom: 10px;
}
.heat i { height: 14px; }
.heat i:nth-child(1) { background: #1e1712; }
.heat i:nth-child(2) { background: #2a240c; }
.heat i:nth-child(3) { background: #3d3410; }
.heat i:nth-child(4) { background: #5c4a12; }
.heat i:nth-child(5) { background: #8a7018; }
.heat i:nth-child(6) { background: #c9a227; }
.heat i:nth-child(7) { background: #d4c08a; }
.heat i:nth-child(8) { background: #eadcc8; }
.heat i:nth-child(n+9) { background: #f4eee0; }
.heat.drift i:nth-child(n+8) { opacity: 0.4; }
.n { font-family: var(--display); font-size: 44px; margin: 0 0 6px; }
.n span { font-size: 18px; color: var(--mute); }
.cta { display: flex; flex-wrap: wrap; gap: 10px; }
.btn { display: inline-flex; align-items: center; padding: 10px 16px; border: 1px solid currentColor; font-size: 14px; font-family: var(--display); letter-spacing: 0.06em; }
.btn.lock { background: var(--oak); color: var(--lane); border-color: var(--oak); }
.btn.line { color: var(--oak); }
.w { width: min(1040px, calc(100% - 40px)); margin: 0 auto; padding: 72px 0; }
.alt { background: #e8dcc0; }
.tri { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; margin-top: 20px; }
.tri article { background: #fff8ee; padding: 16px; }
.tri ul, .io ul, #rules ol { margin: 0; padding-left: 1.1em; }
.steps { padding-left: 1.2em; max-width: 48em; }
.steps li { margin-bottom: 10px; }
.pair { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 24px; }
.pair img { width: 100%; height: 240px; object-fit: cover; }
.pair figcaption { font-size: 13px; color: var(--mute); margin-top: 8px; }
#rules ol {
  background: #fff8ee;
  padding: 16px 16px 16px 36px;
  border-left: 8px solid var(--oil);
  max-width: 46em;
}
.io { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.io > div { background: #fff8ee; padding: 16px; }
.url { margin-top: 18px; font-family: var(--mono); font-size: 13px; }
footer { padding: 20px 24px 40px; color: var(--mute); font-size: 13px; }
@media (max-width: 900px) {
  .tri, .pair, .io { grid-template-columns: 1fr; }
  .nav-toggle { display: inline-block; }
  .bar { flex-wrap: wrap; }
  .nav-links {
    display: none;
    width: 100%;
    flex-direction: column;
    background: #2a1e12;
    padding: 12px;
  }
  .nav-links.open { display: flex; }
  .lane { height: 32vh; }
  h1 { font-size: 32px; }
}