:root {
  --char: #2b2b2b;
  --orange: #f25c19;
  --orange-d: #c9460f;
  --sand: #fff6ef;
  --ash: #f3eee8;
  --line: #e4d6c8;
  --soft: #6b5e55;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--ash);
  color: var(--char);
  line-height: 1.7;
  font-size: 16px;
}

a { color: var(--orange-d); text-decoration: none; }
a:hover { text-decoration: underline; }

.shell { display: grid; grid-template-columns: 230px 1fr; min-height: 100vh; }

.rail {
  background: #2b2b2b;
  color: #f7efe8;
  padding: 28px 20px;
  position: sticky;
  top: 0;
  height: 100vh;
}

.rail .brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 800;
  color: #fff;
  margin-bottom: 28px;
  text-decoration: none;
}

.rail nav { display: flex; flex-direction: column; gap: 8px; }

.rail nav a {
  color: #ecdccf;
  text-decoration: none;
  padding: 10px 12px;
  border-left: 3px solid transparent;
}

.rail nav a.is-current,
.rail nav a:hover {
  background: #3a3a3a;
  border-left-color: var(--orange);
  color: #fff;
  text-decoration: none;
}

.rail .hint { margin-top: 28px; font-size: 12px; color: #b9aaa0; }

.stage { padding: 0 0 48px; }

.banner {
  background: linear-gradient(90deg, #f25c19 0%, #ff8a4c 100%);
  color: #fff;
  padding: 42px 48px 36px;
}

.banner h1 { font-size: clamp(26px, 3.4vw, 38px); line-height: 1.3; margin: 8px 0 14px; }

.banner p { max-width: 720px; color: #fff4ec; }

.act { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 20px; }

.act a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 18px;
  background: #fff;
  color: var(--orange-d);
  font-weight: 800;
  text-decoration: none;
}

.act a.sub { background: transparent; color: #fff; border: 1px solid #fff; }

.chips { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 18px; }

.chips b {
  background: rgba(255,255,255,.16);
  padding: 4px 10px;
  font-size: 13px;
  font-weight: 600;
}

.block { padding: 28px 48px 0; }

.block h2 { font-size: 22px; margin-bottom: 10px; }

.feature-bar {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 16px;
  background: #fff;
  border-top: 4px solid var(--orange);
  padding: 18px 20px;
  margin-bottom: 12px;
}

.feature-bar strong { color: var(--orange-d); font-size: 15px; }

.quad {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.quad article {
  background: #fff;
  padding: 16px;
  border: 1px solid var(--line);
}

.quad h2 { font-size: 19px; }

ol.num {
  background: #fff;
  padding: 16px 16px 16px 40px;
  border-left: 6px solid var(--char);
}

table.grid {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
}

table.grid th, table.grid td { border: 1px solid var(--line); padding: 9px 10px; }
table.grid th { background: var(--char); color: #fff; text-align: left; }

.qa { background: #fff; padding: 14px 16px; margin-bottom: 10px; border-left: 5px solid var(--orange); }
.qa h3 { font-size: 16px; margin-bottom: 6px; }

.base {
  background: #211c19;
  color: #d9cfc7;
  padding: 28px 48px;
  font-size: 13px;
}

.base a { color: #ffb089; }
.ok { color: #ffd19a; margin-bottom: 8px; }
.base nav { display: flex; gap: 14px; margin: 10px 0; }

@media (max-width: 900px) {
  .shell { grid-template-columns: 1fr; }
  .rail { position: relative; height: auto; }
  .rail nav { flex-direction: row; flex-wrap: wrap; }
  .banner, .block, .base { padding-left: 20px; padding-right: 20px; }
  .feature-bar, .quad { grid-template-columns: 1fr; }
}