/* 第2套：功能驱动 · 左侧栏 + 主栏 · 锈橙深灰 */
:root {
  --bg: #f6f1eb;
  --panel: #ffffff;
  --side: #2a3035;
  --side-ink: #d7ddd8;
  --rust: #c45c26;
  --rust-deep: #8f3d12;
  --ink: #1d2226;
  --muted: #5b646c;
  --line: #ddd4c8;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.75;
  font-size: 16px;
}

.shell {
  display: grid;
  grid-template-columns: 248px 1fr;
  min-height: 100vh;
}
aside.rail {
  background: var(--side);
  color: var(--side-ink);
  padding: 28px 22px 40px;
  position: sticky;
  top: 0;
  height: 100vh;
}
.brand {
  display: block;
  color: #fff;
  text-decoration: none;
  font-weight: 800;
  font-size: 26px;
  letter-spacing: 0.08em;
  margin-bottom: 28px;
}
aside.rail nav a {
  display: block;
  color: var(--side-ink);
  text-decoration: none;
  padding: 10px 12px;
  border-left: 3px solid transparent;
  margin: 4px 0;
  font-size: 15px;
}
aside.rail nav a.current {
  background: #3a4248;
  border-left-color: var(--rust);
  color: #fff;
  font-weight: 700;
}
.side-note {
  margin-top: 36px;
  font-size: 13px;
  color: #9aa3aa;
  line-height: 1.65;
}

main.canvas { padding: 0 0 60px; }
.topstrip {
  background: var(--rust);
  color: #fff8f3;
  padding: 10px 36px;
  font-size: 14px;
}
.inner { width: min(880px, calc(100% - 64px)); margin: 0 auto; padding-top: 32px; }

.hero h1 {
  font-size: 30px;
  line-height: 1.35;
  margin: 12px 0 14px;
}
.hero .lead { color: var(--muted); margin-bottom: 18px; }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--rust);
  color: #fff;
  text-decoration: none;
  padding: 11px 20px;
  font-weight: 700;
  border-radius: 4px;
}
.btn-line {
  background: transparent;
  color: var(--rust-deep);
  border: 1px solid var(--rust);
  margin-left: 8px;
}

.intro-panel {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 20px 22px;
  margin: 22px 0;
}
.intro-panel + .intro-panel { margin-top: 14px; }
.intro-panel h2 { font-size: 21px; margin-bottom: 10px; }
.intro-panel p + p { margin-top: 10px; }
.intro-panel ul { margin: 10px 0 0 1.2em; color: var(--muted); }
ol.feat {
  list-style: none;
  counter-reset: f;
  margin: 28px 0;
}
ol.feat li {
  counter-increment: f;
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 18px 20px 18px 72px;
  margin: 12px 0;
  position: relative;
}
ol.feat li::before {
  content: counter(f, decimal-leading-zero);
  position: absolute;
  left: 16px;
  top: 18px;
  font-weight: 800;
  color: var(--rust);
  font-size: 18px;
}
ol.feat h2 { font-size: 20px; margin-bottom: 8px; }

.block { margin: 34px 0; }
.block h2 { font-size: 22px; margin-bottom: 10px; }
.block p + p { margin-top: 10px; }
.block ul { margin: 10px 0 0 1.2em; }

table.grid {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
  background: var(--panel);
}
table.grid th, table.grid td {
  border: 1px solid var(--line);
  padding: 8px 10px;
  text-align: left;
}
table.grid th { background: #efe4d6; }

.faq article { background: var(--panel); border: 1px solid var(--line); padding: 14px 16px; margin: 10px 0; }
.faq h3 { font-size: 16px; margin-bottom: 6px; }

footer {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--muted);
}
footer p { margin: 8px 0; }
footer a { color: var(--rust-deep); }

svg.icon { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; }

@media (max-width: 860px) {
  .shell { grid-template-columns: 1fr; }
  aside.rail { position: relative; height: auto; }
}