:root {
  --rust: #c45c26;
  --rust-d: #8f3d12;
  --slate: #2c3338;
  --paper: #f7f3ee;
  --card: #fffaf4;
  --line: #e2d6c8;
  --quiet: #667079;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--paper);
  color: var(--slate);
  line-height: 1.7;
  display: grid;
  grid-template-columns: 248px 1fr;
  min-height: 100vh;
}
a { color: var(--rust-d); }
.side {
  background: var(--slate);
  color: #e8edf0;
  padding: 28px 20px;
  position: sticky;
  top: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
  gap: 28px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  text-decoration: none;
  font-weight: 700;
  font-size: 1.3rem;
  letter-spacing: 0.08em;
}
.side nav { display: flex; flex-direction: column; gap: 6px; }
.side nav a {
  color: #c9d2d8;
  text-decoration: none;
  padding: 10px 12px;
  border-left: 3px solid transparent;
}
.side nav a[aria-current="page"] {
  color: #fff;
  background: rgba(196,92,38,0.25);
  border-left-color: var(--rust);
}
.side-note { font-size: 0.82rem; color: #9aa6ae; margin-top: auto; }
.main { min-width: 0; }
.hero {
  background: var(--card);
  border-bottom: 4px solid var(--rust);
  padding: 42px 48px 36px;
}
.hero h1 {
  font-size: clamp(1.7rem, 2.6vw, 2.2rem);
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 16px 0 20px;
}
.hero-meta span {
  border: 1px solid var(--line);
  padding: 4px 10px;
  font-size: 0.85rem;
}
.cta {
  display: inline-block;
  background: var(--rust);
  color: #fff;
  text-decoration: none;
  padding: 12px 20px;
  font-weight: 700;
}
.cta.ghost {
  background: transparent;
  color: var(--rust-d);
  border: 1px solid var(--rust);
  margin-left: 10px;
}
.content { padding: 36px 48px 64px; max-width: 880px; }
.content h2 {
  font-size: 1.28rem;
  margin: 36px 0 12px;
  padding-bottom: 6px;
  border-bottom: 1px dashed var(--line);
}
.content h2:first-child { margin-top: 0; }
.content p { margin-bottom: 12px; }
.feat {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 12px 20px;
  background: var(--card);
  border: 1px solid var(--line);
  padding: 18px;
  margin: 16px 0;
}
.feat dt { font-weight: 700; color: var(--rust-d); }
.quote {
  margin: 16px 0;
  padding: 14px 18px;
  background: #fff;
  border-left: 4px solid var(--slate);
  color: var(--quiet);
}
.intro-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin: 14px 0 18px;
}
.intro-pair div {
  background: var(--card);
  border: 1px solid var(--line);
  padding: 14px 16px;
}
.intro-pair h3 { font-size: 1rem; color: var(--rust-d); margin-bottom: 8px; }
@media (max-width: 880px) {
  .intro-pair { grid-template-columns: 1fr; }
}

.faq + .faq { margin-top: 8px; }
.faq {
  border: 1px solid var(--line);
  background: #fff;
  padding: 12px 14px;
}
.faq summary { cursor: pointer; font-weight: 600; }
.faq p { margin-top: 8px; }
.foot {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 0.9rem;
  color: var(--quiet);
}
.foot p { margin-bottom: 8px; }
.foot-nav { display: flex; gap: 14px; margin-bottom: 10px; }

@media (max-width: 880px) {
  body { grid-template-columns: 1fr; }
  .side { position: relative; height: auto; }
  .side nav { flex-direction: row; flex-wrap: wrap; }
  .hero, .content { padding: 24px 20px; }
  .feat { grid-template-columns: 1fr; }
}