/* 课思悠教程中心共用样式（浅色、移动端优先） */
:root {
  --ink: #16233a;
  --ink-soft: #4a5a75;
  --line: #e3e9f2;
  --brand: #2f6bff;
  --brand-soft: #eef3ff;
  --bg: #f6f8fc;
  --card: #ffffff;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.7 -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
}
a { color: var(--brand); }
.wrap { max-width: 880px; margin: 0 auto; padding: 0 20px; }

.site-head {
  background: #fff;
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 10;
}
.site-head .wrap { display: flex; align-items: center; gap: 16px; min-height: 58px; }
.brand { font-weight: 700; color: var(--ink); text-decoration: none; white-space: nowrap; }
.brand span { color: var(--brand); }
.site-head nav { margin-left: auto; display: flex; gap: 14px; font-size: 14px; flex-wrap: wrap; }
.site-head nav a { color: var(--ink-soft); text-decoration: none; }
.site-head nav a:hover { color: var(--brand); }

main { padding: 26px 0 60px; }
.crumb { font-size: 13px; color: var(--ink-soft); margin-bottom: 14px; }
.crumb a { color: var(--ink-soft); }
h1 { font-size: 30px; line-height: 1.35; margin: 6px 0 12px; }
.lead { font-size: 17px; color: var(--ink-soft); margin: 0 0 22px; }
h2 { font-size: 21px; margin: 34px 0 12px; padding-top: 6px; }
h3 { font-size: 17px; margin: 22px 0 8px; }
p { margin: 10px 0; }
ul, ol { padding-left: 22px; margin: 10px 0; }
li { margin: 6px 0; }
code {
  background: #eef2f8;
  border-radius: 5px;
  padding: 1px 6px;
  font-size: 0.94em;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px 20px;
  margin: 16px 0;
}
.callout {
  border-left: 4px solid var(--brand);
  background: var(--brand-soft);
  border-radius: 10px;
  padding: 12px 16px;
  margin: 16px 0;
  font-size: 15px;
}
.callout.warn { border-left-color: #e8a33d; background: #fff7e9; }
.callout.ok { border-left-color: #23a06b; background: #eefaf4; }

.shot { margin: 18px 0; }
.shot img {
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
  display: block;
}
.shot figcaption { font-size: 13px; color: var(--ink-soft); margin-top: 8px; }

.grid { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.tile { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 15px 17px; }
.tile strong { display: block; margin-bottom: 4px; }
.tile p { margin: 0; font-size: 15px; color: var(--ink-soft); }

.linklist { list-style: none; padding: 0; margin: 12px 0; }
.linklist li { border-bottom: 1px dashed var(--line); padding: 10px 0; }
.linklist a { font-weight: 600; text-decoration: none; }
.linklist small { display: block; color: var(--ink-soft); font-weight: 400; margin-top: 2px; }

.faq article { border-bottom: 1px solid var(--line); padding: 12px 0; }
.faq h3 { margin: 0 0 6px; font-size: 16px; }

.cta {
  background: linear-gradient(135deg, #2f6bff, #5b8cff);
  color: #fff;
  border-radius: 14px;
  padding: 20px 22px;
  margin: 28px 0 8px;
}
.cta h2 { color: #fff; margin: 0 0 6px; font-size: 20px; }
.cta p { margin: 0 0 12px; color: #eaf0ff; font-size: 15px; }
.cta a {
  display: inline-block;
  background: #fff;
  color: var(--brand);
  font-weight: 700;
  text-decoration: none;
  border-radius: 999px;
  padding: 9px 20px;
}

footer.site-foot {
  border-top: 1px solid var(--line);
  background: #fff;
  padding: 22px 0;
  font-size: 13px;
  color: var(--ink-soft);
}
footer.site-foot a { color: var(--ink-soft); }

@media (max-width: 640px) {
  h1 { font-size: 24px; }
  h2 { font-size: 19px; }
  .lead { font-size: 16px; }
  .site-head nav { font-size: 13px; gap: 10px; }
}