/* 第1套 ROOT · 手册书脊：米黄纸面 + 藏青书脊 + 衬线正文 */
:root {
  --paper: #f4efe4;
  --paper-deep: #e8e0d0;
  --cream: #fffaf0;
  --spine: #1a3658;
  --spine-ink: #10233c;
  --gold: #9a7540;
  --ink: #1b1914;
  --muted: #5b5348;
  --rule: #cbbda8;
  --rule-soft: #ddd2be;
  --ok: #2d5a3d;
  --danger: #7a2c2c;
  --shadow: rgba(26, 54, 88, 0.1);
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: auto; }

body {
  margin: 0;
  background: var(--paper-deep);
  color: var(--ink);
  font-family: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "STSong", "SimSun", Georgia, serif;
  font-size: 17px;
  line-height: 1.88;
}

img, svg { max-width: 100%; vertical-align: middle; }

a { color: var(--spine); text-underline-offset: 3px; }
a:hover { color: var(--spine-ink); }

.book {
  width: min(1080px, 100%);
  margin: 0 auto;
  background: var(--paper);
  min-height: 100vh;
  box-shadow: 0 0 0 1px var(--rule), 18px 0 40px var(--shadow);
  position: relative;
}

.book::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 16px;
  background: linear-gradient(90deg, var(--spine-ink), var(--spine) 60%, #2a4d86);
}

.book-inner { padding-left: 16px; }

.site-header {
  border-bottom: 1px solid var(--rule);
  background: var(--cream);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 28px 14px 22px;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--spine-ink);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.04em;
}

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

.site-nav a {
  text-decoration: none;
  padding: 6px 12px;
  color: var(--muted);
  border-bottom: 2px solid transparent;
}

.site-nav a:hover { color: var(--spine); }

.site-nav a.active {
  color: var(--spine-ink);
  border-bottom-color: var(--gold);
  font-weight: 700;
}

main { padding: 8px 36px 48px 28px; }

.hero {
  padding: 28px 0 12px;
  border-bottom: 1px dashed var(--rule);
}

.hero-kicker {
  color: var(--gold);
  letter-spacing: 0.18em;
  font-size: 0.78rem;
  margin: 0 0 8px;
}

h1 {
  font-size: 1.85rem;
  line-height: 1.4;
  margin: 0 0 16px;
  color: var(--spine-ink);
}

h2 {
  font-size: 1.35rem;
  margin: 0 0 12px;
  color: var(--spine);
}

h3 {
  font-size: 1.08rem;
  margin: 22px 0 10px;
  color: var(--spine-ink);
}

p { margin: 0 0 14px; }

.hero-meta { color: var(--muted); font-size: 0.92rem; }

.hero-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; margin: 18px 0; }

.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--spine);
  color: #fff;
  text-decoration: none;
  padding: 12px 20px;
  border-radius: 2px;
  font-weight: 700;
}

.btn-download:hover { background: var(--spine-ink); color: #fff; }

.btn-download.is-loading { opacity: 0.7; pointer-events: none; }

.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 16px;
  border: 1px solid var(--rule);
  text-decoration: none;
  color: var(--spine);
}

.btn-note { color: var(--muted); font-size: 0.88rem; }

.notice {
  background: #fff7e8;
  border-left: 4px solid var(--gold);
  padding: 12px 16px;
  margin: 16px 0 24px;
  color: var(--muted);
}

.timeline { margin-top: 8px; }

.chapter {
  padding: 28px 0 8px;
  border-bottom: 1px solid var(--rule-soft);
}

.chapter-kicker {
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--gold);
  margin: 0 0 6px;
}

.icon-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 16px 0 20px;
}

.icon-card {
  background: var(--cream);
  border: 1px solid var(--rule-soft);
  padding: 14px;
}

.icon-card strong { display: block; margin: 8px 0 6px; color: var(--spine-ink); }
.icon-card p { margin: 0; font-size: 0.95rem; color: var(--muted); }

.quote-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin: 16px 0;
}

.quote {
  background: var(--cream);
  border: 1px solid var(--rule);
  padding: 14px 16px;
}

.quote p { margin: 0 0 8px; }
.quote cite { color: var(--muted); font-style: normal; font-size: 0.88rem; }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0 18px;
  font-size: 0.95rem;
}

th, td {
  border: 1px solid var(--rule);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

th { background: #e8efe8; color: var(--spine-ink); }

.faq-list { margin: 0; }
.faq-list dt {
  font-weight: 700;
  margin: 16px 0 6px;
  color: var(--spine-ink);
}
.faq-list dd { margin: 0 0 8px; color: var(--ink); }

.site-footer {
  background: var(--spine-ink);
  color: #d7deea;
  padding: 28px 36px 36px 44px;
  font-size: 0.92rem;
}

.site-footer a { color: #e8c98a; }
.site-footer nav { display: flex; gap: 16px; margin-top: 10px; }
.foot-safe { color: #f0e6d0; }

@media (max-width: 800px) {
  .icon-row, .quote-grid { grid-template-columns: 1fr; }
  main { padding: 8px 18px 36px 16px; }
  h1 { font-size: 1.45rem; }
}

.plat-dl {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin: 14px 0 18px;
}
.plat-btn {
  display: flex;
  flex-direction: column;
  gap: 4px;
  text-decoration: none;
  padding: 12px 10px;
  border: 1px solid currentColor;
  font-weight: 700;
}
.plat-btn small {
  font-weight: 400;
  opacity: 0.75;
  font-size: 0.78rem;
}
.plat-btn:hover { filter: brightness(1.05); }
@media (max-width: 800px) {
  .plat-dl { grid-template-columns: 1fr 1fr; }
}
.plat-btn { background: #fffaf0; color: #1a3658; border-color: #cbbda8; }

@keyframes spin { to { transform: rotate(360deg); } }
.plat-btn.is-loading { opacity: 0.7; pointer-events: none; }