/* Set 19 — sand matrix sheet: brown mast, table-first, twin split. Not a feature brochure. */
:root {
  --sand: #fef3c7;
  --sand-2: #fffbeb;
  --brown: #78350f;
  --brown-deep: #451a03;
  --card: #fffdf6;
  --ink: #431407;
  --text: #5c2b0e;
  --mute: #7c4a1e;
  --line: #f5d08a;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: auto; }

body {
  font-family: "Palatino Linotype", "Songti SC", "STKaiti", "Microsoft YaHei", serif;
  background:
    repeating-linear-gradient(
      90deg,
      rgba(120, 53, 15, 0.035) 0 1px,
      transparent 1px 42px
    ),
    var(--sand);
  color: var(--text);
  line-height: 1.78;
  font-size: 16.5px;
}

a { color: inherit; text-decoration: none; }
svg { display: block; }

.sheet { width: min(1080px, calc(100% - 30px)); margin: 0 auto; }

.mast {
  background: var(--brown);
  color: var(--sand);
}

.mast-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 64px;
}

.word {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  letter-spacing: 0.03em;
}

.navs {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 4px 12px;
  font-size: 13px;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

.navs a { color: #fde68a; padding: 6px 0; }
.navs a:hover,
.navs a:focus { color: #ffffff; }

.grain {
  padding: 34px 0 6px;
}

.grain h1 {
  font-size: clamp(24px, 3vw, 33px);
  line-height: 1.3;
  color: var(--brown-deep);
  margin-bottom: 12px;
}

.grain p { max-width: 46em; margin-bottom: 10px; }

.unit { padding: 30px 0 4px; }

.unit h2 {
  font-size: clamp(20px, 2.3vw, 26px);
  color: var(--brown-deep);
  margin-bottom: 10px;
}

.note { margin-bottom: 16px; max-width: 48em; }

.matrix {
  width: 100%;
  border-collapse: collapse;
  background: var(--card);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 14.5px;
}

.matrix th,
.matrix td {
  border: 1px solid var(--brown);
  padding: 11px 12px;
  text-align: left;
  vertical-align: top;
}

.matrix th {
  background: var(--brown);
  color: var(--sand);
  font-weight: 700;
}

.matrix td:first-child {
  background: #fde68a;
  font-weight: 700;
  color: var(--brown-deep);
  width: 18%;
}

.deep {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.deep article {
  background: var(--card);
  padding: 16px;
  border: 1px solid var(--line);
  box-shadow: 4px 4px 0 var(--brown);
}

.deep .ico {
  color: var(--brown);
  margin-bottom: 8px;
}

.deep h3 { font-size: 17px; color: var(--brown-deep); margin-bottom: 8px; }

.twin {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  background: var(--card);
  border: 2px solid var(--brown);
}

.twin article { padding: 20px 18px; }
.twin article:first-child { border-right: 2px solid var(--brown); }
.twin h3 { color: var(--brown-deep); margin-bottom: 8px; font-size: 18px; }

.bound {
  counter-reset: step;
  display: grid;
  gap: 10px;
}

.bound article {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px;
  background: var(--sand-2);
  padding: 12px 14px;
  border-left: 4px solid var(--brown);
}

.bound article::before {
  counter-increment: step;
  content: counter(step);
  font-weight: 800;
  color: var(--brown);
  font-family: "Segoe UI", sans-serif;
  font-size: 20px;
  line-height: 1;
}

.bound h3 { font-size: 16px; color: var(--ink); margin-bottom: 4px; }

.four {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.four article {
  background: var(--card);
  padding: 16px;
  border-bottom: 3px solid var(--brown);
}

.four h3 { font-size: 16px; color: var(--brown-deep); margin-bottom: 6px; }

.back {
  width: 100%;
  border-collapse: collapse;
  background: var(--card);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

.back th,
.back td {
  border: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}

.back th { background: #fde68a; color: var(--brown-deep); }

.outside {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.outside li {
  list-style: none;
  background: var(--brown);
  color: var(--sand);
  padding: 10px 14px;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 14.5px;
}

.ask details {
  background: var(--card);
  border: 1px solid var(--brown);
  margin-bottom: 10px;
  padding: 12px 14px;
}

.ask summary {
  cursor: pointer;
  font-weight: 700;
  color: var(--brown-deep);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

.ask details p { margin-top: 8px; }

.base {
  margin-top: 36px;
  background: var(--brown-deep);
  color: #fde68a;
  padding: 26px 0 20px;
  font-size: 14.5px;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

.base p { margin-bottom: 8px; max-width: 50em; }
.base .legal { color: #fef3c7; margin-top: 12px; }

@media (max-width: 840px) {
  .mast-row { flex-direction: column; align-items: flex-start; padding: 12px 0; }
  .deep,
  .twin,
  .four { grid-template-columns: 1fr; }
  .twin article:first-child { border-right: 0; border-bottom: 2px solid var(--brown); }
}