/* 第4套 cn：卡片栅格，先平台后功能 */
:root {
  --s4-bg: #fff8f3;
  --s4-ink: #2b2118;
  --s4-mute: #6d5848;
  --s4-line: #edd8c6;
  --s4-orange: #e85d04;
  --s4-orange-d: #c24c03;
  --s4-paper: #ffffff;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: auto; }
body {
  margin: 0;
  background: var(--s4-bg);
  color: var(--s4-ink);
  font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
  font-size: 16.5px;
  line-height: 1.75;
}
img, svg { max-width: 100%; vertical-align: middle; }
a { color: var(--s4-orange-d); }
a:hover { color: var(--s4-orange); }

.s4-head { background: #fff; border-bottom: 3px solid var(--s4-orange); }
.s4-inner { max-width: 1080px; margin: 0 auto; padding: 0 18px; }
.s4-head-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 70px;
  gap: 12px;
}
.s4-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  font-size: 20px;
  font-weight: 800;
}
.s4-nav a {
  text-decoration: none;
  color: var(--s4-mute);
  margin-left: 14px;
  font-weight: 600;
}
.s4-nav a.is-current { color: var(--s4-orange); }

.s4-hero { padding: 28px 0 10px; }
.s4-hero h1 { font-size: 30px; margin: 0 0 12px; }
.s4-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
.s4-grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.s4-card {
  background: var(--s4-paper);
  border: 1px solid var(--s4-line);
  border-radius: 16px;
  padding: 18px;
  box-shadow: 0 6px 0 rgba(232, 93, 4, 0.08);
}
.s4-card h2, .s4-card h3 { margin-top: 8px; }
.s4-sec { padding: 22px 0; }
.s4-sec > h2 { margin: 0 0 12px; font-size: 23px; }
.s4-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--s4-orange);
  color: #fff;
  text-decoration: none;
  padding: 10px 16px;
  border-radius: 999px;
  font-weight: 700;
}
.s4-btn:hover { background: var(--s4-orange-d); color: #fff; }
.s4-btn-ghost {
  display: inline-flex;
  border: 1px solid var(--s4-orange);
  color: var(--s4-orange-d);
  text-decoration: none;
  padding: 9px 14px;
  border-radius: 999px;
  font-weight: 600;
}
.s4-faq dt { font-weight: 700; margin-top: 14px; }
.s4-faq dd { margin: 6px 0 0; color: var(--s4-mute); }
.s4-foot {
  margin-top: 20px;
  padding: 20px 0 32px;
  color: var(--s4-mute);
  font-size: 14px;
}

@media (max-width: 860px) {
  .s4-grid, .s4-grid-4 { grid-template-columns: 1fr; }
  .s4-head-row { flex-wrap: wrap; padding: 10px 0; }
}