/* 第2套：功能驱动 · 暗色侧栏 + 三列卡片 */
:root {
  --bg: #071320;
  --panel: #0b1d36;
  --ink: #e8f1ff;
  --muted: #9bb0c9;
  --cyan: #2ec4b6;
  --line: #1c3a5a;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: "Microsoft YaHei", Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.7;
}
a { color: var(--cyan); }
.shell {
  display: grid;
  grid-template-columns: 240px 1fr;
  min-height: 100vh;
}
.side {
  background: var(--panel);
  border-right: 1px solid var(--line);
  padding: 28px 18px;
  position: sticky;
  top: 0;
  height: 100vh;
}
.brand {
  display: flex;
  gap: 8px;
  align-items: center;
  color: #fff;
  text-decoration: none;
  font-weight: 700;
  font-size: 18px;
  margin-bottom: 28px;
}
.side nav a {
  display: block;
  color: var(--muted);
  text-decoration: none;
  padding: 10px 12px;
  border-radius: 6px;
  margin-bottom: 6px;
}
.side nav a.current, .side nav a:hover {
  background: #123152;
  color: var(--cyan);
}
.main { padding: 36px 48px 64px; max-width: 1080px; }
.hero h1 { font-size: 32px; margin: 0 0 14px; }
.lead { color: var(--muted); }
.chips { display: flex; gap: 8px; flex-wrap: wrap; margin: 18px 0; }
.chips span {
  border: 1px solid var(--cyan);
  color: var(--cyan);
  padding: 3px 10px;
  border-radius: 4px;
  font-size: 12px;
}
.cta-row { display: flex; gap: 10px; flex-wrap: wrap; margin: 20px 0 8px; }
.btn {
  background: var(--cyan);
  color: #04221f;
  text-decoration: none;
  padding: 11px 18px;
  border-radius: 4px;
  font-weight: 700;
}
.btn-ghost { background: transparent; color: var(--cyan); border: 1px solid var(--cyan); }
.feat-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 18px 0;
}
.feat {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 16px;
  min-height: 140px;
}
.feat strong { display: block; color: var(--cyan); margin-bottom: 8px; }
section { margin: 42px 0; }
section h2 { font-size: 22px; border-left: 4px solid var(--cyan); padding-left: 10px; }
table.matrix { width: 100%; border-collapse: collapse; }
table.matrix th, table.matrix td { border: 1px solid var(--line); padding: 10px; }
table.matrix th { background: #123152; }
.faq article { background: var(--panel); border: 1px solid var(--line); padding: 14px 16px; margin: 0 0 12px; }
.faq h3 { margin: 0 0 8px; font-size: 16px; color: var(--cyan); }
.site-footer {
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
  padding-top: 20px;
  margin-top: 40px;
}
@media (max-width: 900px) {
  .shell { grid-template-columns: 1fr; }
  .side { position: relative; height: auto; }
  .feat-grid { grid-template-columns: 1fr; }
  .main { padding: 24px 18px 48px; }
}