:root {
  --indigo: #4338CA;
  --indigo-deep: #312E81;
  --book: #EEF2FF;
  --hist: #FAF5FF;
  --ink: #1E1B4B;
  --muted: #4C4878;
  --line: #C7D2FE;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #F5F3FF;
  color: var(--ink);
  line-height: 1.75;
}

a { color: var(--indigo); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { width: min(1180px, calc(100% - 28px)); margin: 0 auto; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: #fff;
  border-bottom: 2px solid var(--indigo);
}

.header-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 68px;
}

.brand { color: var(--indigo); font-weight: 800; }

.nav { display: flex; flex-wrap: wrap; gap: 8px 14px; font-size: 14px; }
.nav a { color: var(--indigo-deep); }

.hero { padding: 32px 0 8px; }

.hero h1 {
  font-size: clamp(24px, 3.2vw, 34px);
  line-height: 1.35;
  margin-bottom: 12px;
}

.rails {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.rail {
  border-radius: 16px;
  padding: 20px 18px;
  min-height: 160px;
}

.rail-book { background: var(--book); border: 2px solid var(--indigo); }
.rail-hist { background: var(--hist); border: 2px dashed #7C3AED; }

.rail .label {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--indigo);
  margin-bottom: 8px;
}

.section { padding: 28px 0; }

.section h2 {
  font-size: clamp(21px, 2.8vw, 27px);
  color: var(--indigo-deep);
  margin-bottom: 14px;
}

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

.dual article {
  border-radius: 14px;
  padding: 16px;
}

.dual .book { background: var(--book); }
.dual .hist { background: var(--hist); }

.dual h3 { font-size: 17px; margin-bottom: 8px; }

.card-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 16px 0;
}

.indigo-card {
  background: #fff;
  border-top: 4px solid var(--indigo);
  border-radius: 12px;
  padding: 14px;
  color: var(--indigo-deep);
}
.indigo-card svg { display: block; margin-bottom: 8px; color: var(--indigo); }

.steps {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin: 16px 0;
}

.step {
  background: #fff;
  border-radius: 12px;
  padding: 14px;
}

.step b { color: var(--indigo); display: block; margin-bottom: 6px; }

.table-wrap { overflow-x: auto; margin: 16px 0; }

table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
}

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

th { background: var(--indigo); color: #fff; }

.svg-card {
  background: #fff;
  border-radius: 16px;
  padding: 16px;
  margin: 16px 0;
}

.faq-list { display: grid; gap: 12px; }

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

.faq-item h3 {
  background: var(--book);
  border-radius: 12px;
  padding: 14px;
  font-size: 16px;
}

.faq-item p {
  background: var(--hist);
  border-radius: 12px;
  margin: 0;
  padding: 14px;
}

.site-footer {
  background: var(--indigo-deep);
  color: #E0E7FF;
  padding: 28px 0 40px;
  font-size: 14px;
}

.site-footer p { margin-bottom: 8px; }

@media (max-width: 860px) {
  .header-bar { flex-direction: column; align-items: flex-start; padding: 12px 0; }
  .rails, .dual, .card-row, .steps, .faq-item { grid-template-columns: 1fr; }
}