:root {
  --rice: #f4ead4;
  --ink: #1c1410;
  --cinnabar: #b83a2a;
  --indigo: #2a3a6a;
  --ochre: #8a5a32;
  --stone: #3d5a3a;
  --vine: #c4a03a;
  --mute: #6e5a48;
  --line: rgba(28, 20, 16, 0.16);
  --display: "Shippori Mincho", "Noto Serif 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;
  margin-left: 18px;
  color: var(--ink);
  background: var(--rice);
  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: var(--cinnabar); 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: 100%; accent-color: var(--cinnabar); }
.fiber {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 8;
  opacity: 0.18;
  background-image: url("images/texture.webp");
  background-size: 420px auto;
  mix-blend-mode: multiply;
}
.pigment-rail {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  width: 18px;
  display: flex;
  flex-direction: column;
  z-index: 50;
}
.pigment-rail span { flex: 1; }
.pigment-rail .cinnabar { background: var(--cinnabar); }
.pigment-rail .indigo { background: var(--indigo); }
.pigment-rail .ochre { background: var(--ochre); }
.pigment-rail .stone { background: var(--stone); }
.pigment-rail .vine { background: var(--vine); }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 28px; top: 12px; z-index: 80; background: var(--cinnabar); color: #fff; padding: 8px; }
.bar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 28px;
  background: rgba(244, 234, 212, 0.92);
  border-bottom: 1px solid var(--line);
}
.brand { font-family: var(--display); font-weight: 800; letter-spacing: 0.08em; }
.brand small {
  display: block;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: var(--mute);
  font-weight: 400;
}
.nav-toggle {
  display: none;
  background: var(--cinnabar);
  color: var(--rice);
  border: 0;
  padding: 6px 12px;
}
.nav-links { display: flex; gap: 16px; font-size: 14px; flex-wrap: wrap; }
.nav-links a { color: var(--mute); }
.nav-links a.is-active, .nav-links a:hover { color: var(--cinnabar); }
.nav-links .live {
  background: var(--indigo);
  color: var(--rice);
  padding: 6px 12px;
}
.hero {
  display: grid;
  grid-template-columns: minmax(280px, 0.9fr) 1.1fr;
  gap: 0;
  min-height: calc(100vh - 64px);
  align-items: stretch;
}
.sheet {
  position: relative;
  padding: 8vh 36px 7vh 40px;
  background: rgba(244, 234, 212, 0.88);
}
.kento {
  position: absolute;
  width: 28px;
  height: 28px;
  border: 4px solid var(--cinnabar);
}
.kento.tl { top: 18px; left: 18px; border-right: 0; border-bottom: 0; }
.kento.br { right: 18px; bottom: 18px; border-left: 0; border-top: 0; border-color: var(--indigo); }
.kicker {
  font-family: var(--mono);
  letter-spacing: 0.16em;
  font-size: 11px;
  color: var(--cinnabar);
  margin: 0 0 12px;
}
h1, h2, h3 { font-family: var(--display); margin: 0 0 12px; line-height: 1.08; font-weight: 800; }
h1 { font-size: clamp(40px, 6.4vw, 76px); }
h2 { font-size: clamp(24px, 3.2vw, 40px); }
.lead { max-width: 38em; color: var(--mute); }
.demo {
  margin: 22px 0;
  padding: 16px 18px;
  max-width: 28em;
  background: #fff8ee;
  border: 1px solid var(--line);
  box-shadow: 8px 8px 0 var(--indigo);
}
.demo.is-ok { box-shadow: 8px 8px 0 var(--stone); }
.n { font-family: var(--display); font-size: 36px; margin: 0 0 8px; }
.cta { display: flex; flex-wrap: wrap; gap: 10px; }
.btn { display: inline-flex; align-items: center; padding: 10px 16px; border: 1px solid var(--ink); font-size: 14px; }
.btn.fill { background: var(--cinnabar); color: var(--rice); border-color: var(--cinnabar); }
.btn.line { background: transparent; }
.hang { margin: 0; position: relative; }
.hang img { width: 100%; height: 100%; object-fit: cover; min-height: 100%; }
.hang figcaption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 12px 16px;
  background: linear-gradient(transparent, rgba(28, 20, 16, 0.82));
  color: var(--rice);
  font-size: 13px;
}
.w { width: min(1040px, calc(100% - 48px)); margin: 0 auto; padding: 76px 0; }
.alt { background: #efe4cc; }
.tri { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 14px; margin-top: 22px; }
.tri article { background: #fff8ee; padding: 16px 18px; border-top: 6px solid var(--cinnabar); }
.tri article:nth-child(2) { border-top-color: var(--indigo); }
.tri article:nth-child(3) { border-top-color: var(--ochre); }
.tri ul, .io ul, #rules ol { margin: 0; padding-left: 1.15em; }
.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: 28px; }
.pair img { width: 100%; height: 260px; object-fit: cover; }
.pair figcaption { font-size: 13px; color: var(--mute); margin-top: 8px; }
#rules ol {
  background: #fff8ee;
  padding: 18px 18px 18px 36px;
  border-left: 8px solid var(--cinnabar);
  max-width: 46em;
}
.io { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.io > div { background: #fff8ee; padding: 16px 18px; }
.url { margin-top: 18px; font-family: var(--mono); font-size: 13px; }
footer { padding: 20px 28px 40px; color: var(--mute); font-size: 13px; border-top: 1px solid var(--line); }
@media (max-width: 900px) {
  body { margin-left: 12px; }
  .pigment-rail { width: 12px; }
  .hero, .tri, .pair, .io { grid-template-columns: 1fr; }
  .hang img { min-height: 42vh; height: 42vh; }
  .nav-toggle { display: inline-block; }
  .bar { flex-wrap: wrap; }
  .nav-links {
    display: none;
    width: 100%;
    flex-direction: column;
    background: #fff8ee;
    padding: 12px;
  }
  .nav-links.open { display: flex; }
  .sheet { padding: 32px 22px 36px; }
}