/* 学习中心 · 教程页共用样式
   与首页 index.html 同一套设计语言（配色 / 字体 / 顶栏 / 页脚） */

:root{
  --ink:#0A1B2E;--navy:#0D2B4E;--navy-2:#123A66;--blue:#1E6FD9;--blue-l:#3E8BF0;
  --gold:#C9962C;--gold-l:#E8B75A;--bg:#F5F8FC;--card:#FFF;--line:#E3EAF3;
  --txt:#1C2B3D;--txt-2:#5A6B82;--risk:#8C2F2F;--risk-bg:#FDF3F0;--ok:#0E7A52;
  --shadow:0 10px 30px rgba(13,43,78,.08);--r:14px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:92px}
body{
  font-family:"Inter","Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  color:var(--txt);background:var(--bg);line-height:1.78;-webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
.wrap{width:min(1180px,92%);margin:0 auto}

/* ---------- 顶部合规条 ---------- */
.geo-bar{background:var(--ink);color:#C7D4E4;font-size:12.5px;line-height:1.5;padding:9px 0;letter-spacing:.02em}
.geo-bar .wrap{display:flex;gap:10px;align-items:flex-start;justify-content:space-between}
.geo-bar .wrap > div:first-child{flex:1 1 auto;min-width:0}
.geo-bar strong{color:var(--gold-l);font-weight:600}
.geo-bar .x{cursor:pointer;opacity:.65;font-size:16px;line-height:1;flex-shrink:0}
.geo-bar .x:hover{opacity:1}

/* ---------- 导航 ---------- */
header.nav{position:sticky;top:0;z-index:80;background:rgba(255,255,255,.92);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.nav-in{display:flex;align-items:center;justify-content:space-between;height:68px}
.logo{display:flex;align-items:center;gap:11px}
.logo-mark{
  width:38px;height:38px;border-radius:10px;flex-shrink:0;
  background:linear-gradient(135deg,var(--navy) 0%,var(--blue) 100%);
  display:flex;align-items:center;justify-content:center;
  color:#fff;font-weight:800;font-size:17px;letter-spacing:.5px;
}
.logo-name{font-weight:800;font-size:18px;color:var(--ink);letter-spacing:.01em}
.logo-sub{font-size:11px;color:var(--txt-2);letter-spacing:.06em;margin-top:-2px}
.nav-links{display:flex;gap:clamp(12px,1.3vw,22px);align-items:center;font-size:14px;font-weight:500;color:#31425A;white-space:nowrap}
.nav-links a:hover{color:var(--blue)}
.nav-links a.on{color:var(--blue);font-weight:700}
.nav-cta{display:flex;gap:10px;align-items:center}
.burger{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:8px}
.burger span{width:22px;height:2px;background:var(--ink);border-radius:2px}

/* ---------- 按钮 ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:13px 26px;border-radius:10px;font-weight:600;font-size:15px;cursor:pointer;border:none;transition:.22s;white-space:nowrap}
.btn-sm{padding:9px 18px;font-size:13.5px;border-radius:9px}
.btn-g{background:linear-gradient(135deg,var(--gold),#B07E1E);color:#fff;box-shadow:0 8px 22px rgba(201,150,44,.32)}
.btn-g:hover{transform:translateY(-2px)}
.btn-o{background:transparent;color:#fff;border:1.5px solid rgba(255,255,255,.42)}
.btn-o:hover{background:rgba(255,255,255,.12);border-color:#fff}
.btn-p{background:linear-gradient(135deg,var(--blue),var(--navy-2));color:#fff;box-shadow:0 8px 22px rgba(30,111,217,.32)}
.btn-p:hover{transform:translateY(-2px)}

/* ---------- 页头 ---------- */
.page-head{background:linear-gradient(150deg,#0A1B2E 0%,#123A66 62%,#1B4C86 100%);color:#fff;padding:38px 0 46px;position:relative;overflow:hidden}
.page-head::after{content:"";position:absolute;width:420px;height:420px;border-radius:50%;background:rgba(255,255,255,.05);top:-180px;right:-90px}
.crumb{font-size:12.5px;color:#8FA3BB;margin-bottom:18px;position:relative}
.crumb a{color:#B9C9DC}
.crumb a:hover{color:var(--gold-l)}
.crumb span{margin:0 7px;opacity:.5}
.page-head h1{font-size:clamp(24px,3.4vw,33px);font-weight:900;line-height:1.35;letter-spacing:-.01em;position:relative;max-width:820px}
.page-head .lede{margin-top:14px;font-size:15.5px;color:#C6D5E6;max-width:760px;position:relative}
.page-head .meta{margin-top:18px;display:flex;flex-wrap:wrap;gap:8px 16px;font-size:12.5px;color:#8FA3BB;position:relative}
.page-head .meta b{color:var(--gold-l);font-weight:600}

/* ---------- 正文布局 ---------- */
.doc{display:grid;grid-template-columns:minmax(0,1fr) 250px;gap:46px;align-items:start;padding:44px 0 10px}
article{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:44px 46px;box-shadow:var(--shadow);min-width:0}
article > *:first-child{margin-top:0}

/* 排版 */
article h2{
  font-size:21px;font-weight:800;color:var(--ink);line-height:1.45;
  margin:46px 0 14px;padding-left:14px;border-left:4px solid var(--gold);
}
article h2:first-of-type{margin-top:0}
article h3{font-size:16.5px;font-weight:700;color:var(--navy);margin:26px 0 8px}
article p{margin:0 0 14px;font-size:15px;color:#2C3B4D}
article strong{color:var(--ink);font-weight:700}
article a.inline{color:var(--blue);font-weight:600;border-bottom:1px solid rgba(30,111,217,.3)}
article a.inline:hover{border-color:var(--blue)}
article code{background:#F0F5FB;border:1px solid var(--line);border-radius:4px;padding:1px 5px;font-family:ui-monospace,"SFMono-Regular",Consolas,monospace;font-size:13px;color:var(--navy);white-space:nowrap}
article ul,article ol{margin:0 0 16px;padding-left:22px}
article li{font-size:15px;margin:7px 0;color:#2C3B4D}
article li::marker{color:var(--blue)}
article ul.plain{list-style:none;padding-left:0}
article ul.plain li{position:relative;padding-left:20px}
article ul.plain li::before{content:"";position:absolute;left:2px;top:11px;width:6px;height:6px;border-radius:50%;background:var(--gold)}

/* 表格 */
.tbl-wrap{overflow-x:auto;margin:18px 0 22px;border:1px solid var(--line);border-radius:10px}
table{width:100%;border-collapse:collapse;font-size:14.2px;min-width:520px}
th,td{padding:11px 14px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
thead th{background:#F0F5FB;font-size:12.5px;color:#41536C;font-weight:700;white-space:nowrap}
tbody tr:last-child td{border-bottom:none}
td.num{font-variant-numeric:tabular-nums;font-weight:600;white-space:nowrap}
td.pos{color:var(--ok);font-variant-numeric:tabular-nums;font-weight:600}
td.neg{color:var(--risk);font-variant-numeric:tabular-nums;font-weight:600}

/* 提示块 */
.note,.warn,.tip-box{border-radius:10px;padding:16px 18px;margin:20px 0;font-size:14.2px;line-height:1.75}
.note{background:#F1F6FD;border:1px solid #D5E5F8;color:#1E3A5C}
.note b{display:block;margin-bottom:4px;color:var(--blue)}
.warn{background:var(--risk-bg);border:1px solid #F1D9D3;color:#6E2A2A}
.warn b{display:block;margin-bottom:4px;color:var(--risk)}
.tip-box{background:linear-gradient(140deg,#0D2B4E,#1E6FD9);color:#EAF2FE;border:none}
.tip-box b{display:block;margin-bottom:6px;color:var(--gold-l);font-size:12px;letter-spacing:.1em}

/* 公式 / 示例 */
.formula{background:#FAFCFF;border:1px dashed #C9D9EC;border-radius:10px;padding:14px 18px;margin:16px 0;font-family:ui-monospace,"SFMono-Regular",Consolas,monospace;font-size:13.6px;color:var(--navy);overflow-x:auto;white-space:nowrap}
.calc{background:#FAFCFF;border:1px solid var(--line);border-left:3px solid var(--blue);border-radius:8px;padding:16px 18px;margin:18px 0}
.calc .h{font-size:12px;font-weight:700;letter-spacing:.08em;color:var(--blue);margin-bottom:8px}
.calc p{margin:5px 0;font-size:14px;color:#2C3B4D}
.calc .res{margin-top:10px;padding-top:9px;border-top:1px dashed var(--line);font-weight:700;color:var(--ink)}

/* 术语 / 卡片 */
.kv{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:18px 0}
.kv-item{border:1px solid var(--line);border-radius:10px;padding:13px 15px;background:#FAFCFF}
.kv-item dt{font-size:13.5px;font-weight:700;color:var(--navy)}
.kv-item dd{font-size:13px;color:var(--txt-2);margin-top:3px;line-height:1.65}

/* 清单 */
.chk{list-style:none;padding:0;margin:16px 0}
.chk li{position:relative;padding-left:28px;margin:9px 0;font-size:14.6px}
.chk li::before{
  content:"✓";position:absolute;left:0;top:1px;width:18px;height:18px;border-radius:5px;
  background:#E7F4EE;color:var(--ok);font-size:12px;font-weight:700;display:flex;align-items:center;justify-content:center;
}

/* 目录 */
.toc{position:sticky;top:96px;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:20px 20px 16px;box-shadow:var(--shadow)}
.toc .t{font-size:11.5px;font-weight:700;letter-spacing:.12em;color:var(--txt-2);margin-bottom:10px}
.toc ol{list-style:none;counter-reset:toc;padding:0;margin:0}
.toc li{counter-increment:toc;margin:0}
.toc li a{display:block;padding:6px 0 6px 24px;font-size:13.2px;color:#41536C;position:relative;line-height:1.5;border-radius:6px}
.toc li a::before{content:counter(toc);position:absolute;left:0;top:6px;font-size:11px;color:#9BAABE;font-variant-numeric:tabular-nums}
.toc li a:hover{color:var(--blue);background:#F5F9FF}

/* 相关教程 */
.next{margin-top:52px;padding-top:26px;border-top:1px solid var(--line)}
.next .t{font-size:12px;font-weight:700;letter-spacing:.1em;color:var(--txt-2);margin-bottom:14px}
.next-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.next-card{display:block;border:1px solid var(--line);border-radius:11px;padding:16px 18px;background:#FAFCFF;transition:.22s}
.next-card:hover{border-color:#BBD4F2;transform:translateY(-3px);box-shadow:var(--shadow)}
.next-card .k{font-size:11px;font-weight:700;letter-spacing:.08em;color:var(--blue);margin-bottom:4px}
.next-card h4{font-size:15px;font-weight:700;color:var(--ink);margin-bottom:2px}
.next-card p{font-size:12.5px;color:var(--txt-2);margin:0}

/* 底部 CTA */
.cta-band{padding:8px 0 58px}
.cta-in{background:linear-gradient(150deg,#0A1B2E 0%,#123A66 70%,#1B4C86 100%);border-radius:16px;padding:36px 40px;color:#fff;display:flex;gap:26px;align-items:center;justify-content:space-between;flex-wrap:wrap}
.cta-in h3{font-size:21px;font-weight:800;margin-bottom:6px}
.cta-in p{font-size:13.8px;color:#B9C9DC;max-width:640px}
.cta-in .btns{display:flex;gap:12px;flex-wrap:wrap}

/* ---------- 页脚 ---------- */
footer{background:var(--ink);color:#8FA3BB;font-size:13px;padding:40px 0 26px}
footer .f-top{display:flex;gap:26px;justify-content:space-between;flex-wrap:wrap;padding-bottom:20px;border-bottom:1px solid rgba(255,255,255,.1)}
footer .f-nav{display:flex;gap:18px;flex-wrap:wrap;font-size:13.5px}
footer .f-nav a{color:#C6D5E6}
footer .f-nav a:hover{color:var(--gold-l)}
footer .f-legal{padding-top:18px;font-size:12px;line-height:1.75;color:#7C8FA6}
footer .f-legal b{color:#A9BDD4}
footer .copy{margin-top:14px;font-size:12px;color:#6C7F96}

/* ---------- 返回顶部 ---------- */
.top-btn{
  position:fixed;right:20px;bottom:24px;z-index:70;width:42px;height:42px;border-radius:11px;
  background:rgba(13,43,78,.86);color:#fff;display:flex;align-items:center;justify-content:center;
  font-size:16px;box-shadow:0 8px 20px rgba(13,43,78,.28);opacity:0;pointer-events:none;transition:.25s;
}
.top-btn.show{opacity:1;pointer-events:auto}
.top-btn:hover{background:var(--blue)}

/* ---------- 响应式 ---------- */
@media(max-width:1280px){
  .nav-links{font-size:13.5px;gap:12px}
  header.nav .logo-name{font-size:16px}
  header.nav .logo-sub{display:none}
  header.nav .logo-mark{width:34px;height:34px;font-size:15px}
}
@media(min-width:641px){.logo-name{white-space:nowrap}}
@media(max-width:1160px){
  .nav-links{display:none}
  .nav-links.open{
    display:flex;flex-direction:column;position:absolute;top:68px;left:0;right:0;
    background:#fff;border-bottom:1px solid var(--line);padding:18px 6%;gap:14px;box-shadow:var(--shadow);
  }
  .burger{display:flex}
  .nav-cta .btn-o-c{display:none}
}
@media(max-width:1000px){
  .doc{grid-template-columns:1fr;gap:0;padding-top:34px}
  .toc{display:none}
  article{padding:34px 26px}
}
@media(max-width:640px){
  .geo-bar .wrap{flex-direction:row}
  .logo-name{font-size:14px}
  .logo-mark{width:34px;height:34px;font-size:15px}
  .page-head{padding:28px 0 34px}
  .page-head .lede{font-size:14.2px}
  article{padding:28px 20px}
  article h2{font-size:19px;margin-top:38px}
  article p,article li{font-size:14.4px}
  .kv{grid-template-columns:1fr}
  .next-grid{grid-template-columns:1fr}
  .cta-in{padding:28px 22px}
  .cta-in h3{font-size:18px}
}