:root {
  --room: #1c1816;
  --room-2: #2a221e;
  --cinnabar: #8b1e1e;
  --seal: #c43a2a;
  --rice: #f4ead6;
  --lamp: #f7e7b0;
  --ink: #1a1412;
  --mute: #7a6a5c;
  --display: "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: 70px; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--rice);
  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: 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: min(280px, 100%); accent-color: var(--cinnabar); }
.grain {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 6;
  opacity: 0.14;
  background-image: url("images/texture.webp");
  background-size: 280px auto;
  mix-blend-mode: multiply;
}
.skip { position: absolute; left: -999px; }
.skip:focus { left: 12px; top: 12px; z-index: 80; background: var(--cinnabar); color: var(--rice); padding: 8px; }
.spine {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 22px;
  background: var(--cinnabar);
  color: var(--rice);
  border-bottom: 8px solid #5a1212;
}
.brand { font-family: var(--display); font-weight: 700; }
.brand small {
  display: block;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: #e8c8b8;
  font-weight: 400;
}
.nav-toggle {
  display: none;
  background: var(--rice);
  color: var(--cinnabar);
  border: 0;
  padding: 6px 12px;
}
.folder-links { display: flex; gap: 14px; font-size: 14px; flex-wrap: wrap; }
.folder-links a { color: #e8c8b8; }
.folder-links a.is-active, .folder-links a:hover { color: var(--rice); }
.folder-links .live { background: var(--rice); color: var(--cinnabar); padding: 6px 12px; }
.desk {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  min-height: calc(100vh - 58px);
}
.desk figure { margin: 0; }
.desk img { width: 100%; height: 100%; object-fit: cover; min-height: 100%; }
.light {
  padding: 7vh 32px;
  background: var(--lamp);
  box-shadow: inset 0 0 80px rgba(255, 250, 220, 0.7);
}
.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: 1.2; }
h1 { font-size: clamp(30px, 4.4vw, 48px); }
h2 { font-size: clamp(22px, 2.8vw, 34px); }
.lead { max-width: 40em; color: #4a3a32; }
.sheet {
  margin: 20px 0;
  padding: 14px 16px;
  background: var(--rice);
  border: 1px solid #c4b090;
  box-shadow: 4px 4px 0 #5a1212;
  max-width: 30em;
}
.sheet.is-ok { box-shadow: 4px 4px 0 #2f6b45; border-color: #2f6b45; }
.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; }
.btn.cinnabar { background: var(--cinnabar); color: var(--rice); border-color: var(--cinnabar); }
.btn.line { color: var(--ink); }
.w { width: min(1040px, calc(100% - 40px)); margin: 0 auto; padding: 72px 0; }
.dark { background: var(--room); color: var(--rice); }
.dark .kicker { color: #e07060; }
.tri { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; margin-top: 20px; }
.tri article { background: #fff8ee; color: var(--ink); padding: 16px; }
.dark .tri article { background: var(--room-2); color: var(--rice); }
.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: #c4b090; margin-top: 8px; }
#need, #gap, #rules { background: var(--rice); }
#rules ol {
  background: #fff8ee;
  padding: 16px 16px 16px 36px;
  border-left: 8px solid var(--cinnabar);
  max-width: 46em;
}
.io { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.io > div { background: var(--room-2); 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) {
  .desk, .tri, .pair, .io { grid-template-columns: 1fr; }
  .desk img { min-height: 42vh; height: 42vh; }
  .nav-toggle { display: inline-block; }
  .spine { flex-wrap: wrap; }
  .folder-links {
    display: none;
    width: 100%;
    flex-direction: column;
    background: #5a1212;
    padding: 12px;
  }
  .folder-links.open { display: flex; }
  .light { padding: 28px 18px 36px; }
}