/* ============================================================
   二级页面共用样式（使用教程 / 关于我们 / 用户协议 / 隐私政策）
   与 index.html 内联样式同一套主题：美图 AI 风白底蓝色科技风
   ============================================================ */
:root {
  --primary: #3F86F2;
  --primary-deep: #2668D9;
  --ink: #1D2129;
  --ink-2: #606266;
  --ink-3: #909399;
  --line: #EBEEF5;
  --bg: #F5F7FA;
  --card: #FFFFFF;
  --radius: 16px;
  --shadow: 0 8px 30px rgba(31, 76, 158, .10);
  --shadow-sm: 0 2px 10px rgba(31, 76, 158, .07);
}
* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--ink); font-size: 15px; line-height: 1.75;
  min-height: 100vh; display: flex; flex-direction: column;
}

/* ===== 顶部导航（与主页一致） ===== */
.nav {
  position: sticky; top: 0; z-index: 30;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 20px; backdrop-filter: blur(14px);
  background: rgba(255,255,255,.85); border-bottom: 1px solid var(--line);
}
.nav .brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 17px; color: var(--ink); text-decoration: none; }
.nav .brand .logo {
  width: 30px; height: 30px; border-radius: 9px; display: grid; place-items: center;
  background: linear-gradient(135deg, #5CA6FF, var(--primary-deep)); color: #fff; font-size: 15px;
}
.nav .menu { display: flex; gap: 28px; font-size: 14.5px; }
.nav .menu a { color: var(--ink-2); text-decoration: none; transition: color .15s; }
.nav .menu a:hover, .nav .menu a.on { color: var(--primary); }

/* ===== 页面标题横幅：浅蓝渐变（与主页 hero 同源） ===== */
.page-hero {
  text-align: center; padding: 46px 24px 54px; position: relative; overflow: hidden;
  background: linear-gradient(180deg, #EAF2FE 0%, #F7FAFF 80%, var(--bg) 100%);
}
.page-hero h1 { font-size: 27px; letter-spacing: 1px; }
.page-hero p { color: var(--ink-2); font-size: 14px; margin-top: 8px; }

/* ===== 正文区 ===== */
.page-body { flex: 1; width: 100%; max-width: 860px; margin: 0 auto; padding: 30px 20px 64px; }
.card {
  background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow-sm);
  padding: 26px 28px; margin-bottom: 18px;
}
.card h2 { font-size: 18px; margin-bottom: 12px; color: var(--ink); }
.card h2 .no {
  display: inline-grid; place-items: center; width: 26px; height: 26px; border-radius: 8px;
  background: linear-gradient(135deg, #5CA6FF, var(--primary-deep)); color: #fff;
  font-size: 14px; margin-right: 9px; vertical-align: -4px;
}
.card h3 { font-size: 15px; margin: 16px 0 6px; }
.card p { color: var(--ink-2); font-size: 14px; margin-bottom: 8px; }
.card ul, .card ol { margin: 4px 0 10px 20px; color: var(--ink-2); font-size: 14px; }
.card li { margin-bottom: 4px; }
.card .muted { color: var(--ink-3); font-size: 12.5px; }
.card a { color: var(--primary); }

/* FAQ 折叠条 */
details.faq {
  background: var(--card); border-radius: 13px; box-shadow: var(--shadow-sm);
  padding: 15px 20px; margin-bottom: 12px;
}
details.faq summary { font-size: 14.5px; font-weight: 600; cursor: pointer; list-style: none; position: relative; padding-right: 26px; }
details.faq summary::after { content: "+"; position: absolute; right: 2px; top: 0; color: var(--primary); font-size: 18px; transition: transform .18s; }
details.faq[open] summary::after { transform: rotate(45deg); }
details.faq p { color: var(--ink-2); font-size: 13.5px; margin-top: 8px; }

/* 联系信息表 */
.contact-list { list-style: none; margin: 0; }
.contact-list li { display: flex; gap: 12px; padding: 10px 0; border-bottom: 1px dashed var(--line); font-size: 14px; }
.contact-list li:last-child { border-bottom: none; }
.contact-list b { color: var(--ink); white-space: nowrap; min-width: 70px; }
.contact-list span { color: var(--ink-2); }

/* 返回首页按钮 */
.btn-back {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 46px; padding: 0 34px; border-radius: 13px; font-size: 15px; font-weight: 600;
  color: #fff; text-decoration: none;
  background: linear-gradient(135deg, #5CA6FF, var(--primary-deep));
  box-shadow: 0 6px 18px rgba(63,134,242,.35); transition: all .16s;
}
.btn-back:hover { filter: brightness(1.06); transform: translateY(-1px); }
.center { text-align: center; margin-top: 26px; }

/* ===== 页脚：与主页完全一致的深色多列版 ===== */
.site-footer {
  background: #1B2331; color: #A6B0C3;
  padding: 44px 24px calc(24px + env(safe-area-inset-bottom));
  font-size: 13px;
}
.site-footer .ft-cols {
  max-width: 980px; margin: 0 auto; display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.6fr; gap: 28px;
}
.site-footer .ft-brand { display: flex; align-items: center; gap: 9px; color: #fff; font-weight: 700; font-size: 16px; margin-bottom: 10px; }
.site-footer .ft-brand .logo {
  width: 28px; height: 28px; border-radius: 8px; display: grid; place-items: center;
  background: linear-gradient(135deg, #5CA6FF, var(--primary-deep)); font-size: 14px;
}
.site-footer .ft-slogan { font-size: 12.5px; line-height: 1.7; color: #7E8AA0; }
.site-footer h4 { color: #E8ECF4; font-size: 14px; margin-bottom: 12px; font-weight: 600; }
.site-footer .ft-cols ul { list-style: none; }
.site-footer .ft-cols li { margin-bottom: 8px; }
.site-footer .ft-cols a { color: #A6B0C3; text-decoration: none; transition: color .15s; }
.site-footer .ft-cols a:hover { color: #fff; }
.site-footer .ft-contact li { display: flex; gap: 8px; font-size: 12.5px; line-height: 1.6; }
.site-footer .ft-contact b { color: #C7CFDD; font-weight: 600; white-space: nowrap; }
.site-footer .ft-bottom {
  max-width: 980px; margin: 32px auto 0; padding-top: 18px;
  border-top: 1px solid rgba(255,255,255,.08); text-align: center;
  font-size: 12px; color: #7E8AA0;
}
.site-footer .ft-icp { margin-top: 4px; }
.site-footer .ft-icp a { color: #7E8AA0; text-decoration: none; }
.site-footer .ft-icp a:hover { color: #fff; text-decoration: underline; }

/* ===== 手机端适配 ===== */
@media (max-width: 640px) {
  body { font-size: 14px; }
  .nav { padding: 10px 14px; }
  .nav .menu { display: none; }   /* 移动端隐藏导航菜单，页脚保留同样入口 */
  .page-hero { padding: 34px 18px 40px; }
  .page-hero h1 { font-size: 22px; }
  .page-body { padding: 22px 14px 48px; }
  .card { padding: 20px 18px; }
  .site-footer .ft-cols { grid-template-columns: 1fr 1fr; gap: 22px; }
  .site-footer .ft-cols > div:first-child, .site-footer .ft-contact-col { grid-column: 1 / -1; }
}