/* 第2套：功能驱动 · 单栏阅读 · 墨黑顶栏 + 金色按钮 · 大号序号行 */
:root {
  --bg: #f8f8f6;
  --ink: #111118;
  --dim: #4a4a55;
  --gold: #c9a227;
  --gold-ink: #1a1508;
  --bar: #111118;
  --rule: #e4e0d4;
  --paper: #ffffff;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Segoe UI", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.7;
}

.topbar {
  background: var(--bar);
  color: #f3efe4;
  position: sticky;
  top: 0;
  z-index: 20;
}
.topbar-inner {
  max-width: 860px;
  margin: 0 auto;
  padding: 12px 20px;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
}
.brand {
  color: #f3efe4;
  text-decoration: none;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.brand small { display: none; }
.nav-inline a {
  color: #cfc8b6;
  text-decoration: none;
  margin-left: 22px;
  font-size: 14px;
  border-bottom: 2px solid transparent;
  padding-bottom: 2px;
}
.nav-inline a.now { color: var(--gold); border-bottom-color: var(--gold); }

.lead-block {
  background: var(--bar);
  color: #f3efe4;
  padding: 48px 20px 56px;
}
.lead-block .wrap { max-width: 860px; margin: 0 auto; }
.lead-block h1 {
  font-size: 30px;
  font-weight: 650;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
  line-height: 1.35;
}
.lead-block p { color: #d2ccbe; max-width: 40em; }
.gold-btn {
  display: inline-block;
  margin-top: 12px;
  background: var(--gold);
  color: var(--gold-ink);
  text-decoration: none;
  padding: 12px 20px;
  font-weight: 700;
}
.gold-btn.inv {
  background: transparent;
  color: var(--gold);
  border: 1px solid var(--gold);
  margin-left: 10px;
}

.wrap { max-width: 860px; margin: 0 auto; padding: 0 20px; }

.feat {
  display: grid;
  grid-template-columns: 88px 1fr;
  gap: 8px 20px;
  padding: 36px 0;
  border-bottom: 1px solid var(--rule);
}
.feat .num {
  font-size: 42px;
  font-weight: 700;
  color: var(--gold);
  line-height: 1;
  font-variant-numeric: tabular-nums;
}
.feat h2 {
  margin: 0 0 10px;
  font-size: 20px;
  font-weight: 650;
}
.feat p { margin: 0 0 10px; color: var(--dim); }

.plain {
  padding: 40px 0;
}
.plain h2 { font-size: 20px; margin: 0 0 12px; }
.plain p { color: var(--ink); }

dl.qa dt { margin-top: 18px; font-weight: 700; }
dl.qa dd { margin: 6px 0 0; color: var(--dim); }

.foot {
  background: var(--bar);
  color: #cfc8b6;
  padding: 32px 20px 48px;
  font-size: 13px;
}
.foot .wrap a { color: var(--gold); margin-right: 16px; }

@media (max-width: 640px) {
  .topbar-inner { flex-direction: column; gap: 10px; }
  .nav-inline a { margin-left: 0; margin-right: 16px; }
  .feat { grid-template-columns: 1fr; }
  .gold-btn.inv { margin-left: 0; margin-top: 10px; display: inline-block; }
}