:root {
  --bg: #f4f7fb;
  --card: #fff;
  --text: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --brand: #dc2626;
  --brand-soft: #fee2e2;
  --accent: #2563eb;
}
* { box-sizing: border-box; }
html, body {
  margin: 0;
  padding: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(1200px 500px at 10% -10%, #fee2e2 0%, transparent 55%),
    radial-gradient(900px 400px at 100% 0%, #dbeafe 0%, transparent 50%),
    var(--bg);
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 16px 64px;
}
.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 20px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 20px;
}
.brand i {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--brand);
  color: #fff;
  display: grid;
  place-items: center;
  font-style: normal;
}
.nav a {
  margin-left: 14px;
  color: var(--muted);
  font-size: 14px;
}
.layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 16px;
}
.side, .main {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
}
.side { padding: 14px; }
.side input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px 10px;
  margin-bottom: 10px;
}
.side a {
  display: block;
  padding: 8px 10px;
  border-radius: 8px;
  color: var(--text);
  font-size: 14px;
}
.side a.on, .side a:hover {
  background: var(--brand-soft);
  color: var(--brand);
  text-decoration: none;
}
.group { margin: 12px 0 6px; color: var(--muted); font-size: 12px; }
.main { padding: 22px 24px; min-height: 560px; }
.main h1 { margin: 0 0 10px; font-size: 24px; }
.main h2 { margin: 22px 0 8px; font-size: 18px; }
.main p, .main li { line-height: 1.7; color: #374151; }
.tag {
  display: inline-block;
  background: var(--brand-soft);
  color: var(--brand);
  border-radius: 999px;
  padding: 2px 10px;
  font-size: 12px;
  margin-bottom: 10px;
}
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 10px;
  margin: 14px 0 8px;
}
.card {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px;
  background: #fafafa;
}
.card b { display: block; margin-bottom: 4px; }
.card span { color: var(--muted); font-size: 13px; }
.foot {
  margin-top: 18px;
  color: var(--muted);
  font-size: 12px;
}
@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; }
  .nav a { margin-left: 8px; }
}