/* ============================================================
   视频教程中心 video.asp 样式
   配色沿用 style.css 的 --brand 体系，与 download.css 统一
   ============================================================ */
:root{
  --brand:#1656c8; --brand-d:#0f3f96; --brand-l:#eaf1fb;
  --ink:#1b2735; --muted:#5b6b80; --line:#e6ebf2; --bg:#f6f8fc;
  --radius:14px; --shadow:0 18px 40px -22px rgba(15,71,143,.35);
}

/* ---------- 页头 ---------- */
.v-head{background:linear-gradient(180deg,#eef4fb,#f6f8fc);border-bottom:1px solid var(--line);padding:42px 0 28px}
.v-head h1{font-size:clamp(28px,4vw,40px);font-weight:800;color:var(--brand-d);margin:0}
.v-lead{color:var(--muted);font-size:16px;line-height:1.8;margin-top:14px}
.v-lead b{color:var(--brand-d)}
.v-stats{display:flex;gap:30px;margin-top:20px;flex-wrap:wrap}
.v-stats b{display:block;font-size:22px;font-weight:800;color:var(--brand-d)}
.v-stats span{font-size:13px;color:var(--muted)}

/* ---------- 精选大图 ---------- */
.hero{display:grid;grid-template-columns:1.25fr 1fr;gap:32px;align-items:center;padding:34px 0 10px}
.hero .hthumb{position:relative;border-radius:16px;overflow:hidden;box-shadow:var(--shadow);aspect-ratio:16/9;background:#0f1f38}
.hero .hthumb svg{width:100%;height:100%;display:block}
.hero .hplay{position:absolute;inset:0;display:grid;place-items:center}
.hero .hplay span{width:66px;height:66px;border-radius:50%;background:rgba(255,255,255,.92);display:grid;place-items:center;transition:.2s;box-shadow:0 10px 30px -8px rgba(0,0,0,.5)}
.hero .hplay span::after{content:"";border-style:solid;border-width:13px 0 13px 22px;border-color:transparent transparent transparent var(--brand);margin-left:5px}
.hero .hthumb:hover .hplay span{transform:scale(1.1);background:#fff}
.hero .htxt .tag{display:inline-block;background:var(--brand-l);color:var(--brand);font-weight:700;font-size:12px;padding:4px 11px;border-radius:999px;margin-bottom:12px}
.hero .htxt h2{font-size:26px;font-weight:800;color:var(--brand-d);margin-bottom:10px}
.hero .htxt p{color:var(--muted);font-size:15px;line-height:1.7;margin-bottom:16px}
.hero .htxt .meta{display:flex;gap:18px;font-size:13px;color:var(--muted);margin-bottom:18px;flex-wrap:wrap}
.hero .htxt .meta b{color:var(--ink)}

/* ---------- 布局：左导航 + 右内容 ---------- */
.layout{display:grid;grid-template-columns:248px 1fr;gap:34px;padding:36px 0 64px;align-items:start}
.side{position:sticky;top:88px;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:14px}
.side .search{display:flex;align-items:center;gap:8px;background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:9px 11px;margin-bottom:12px}
.side .search .si{font-size:14px}
.side .search input{border:0;background:transparent;outline:none;font-size:13px;width:100%;color:var(--ink)}
.side .s-title{font-size:12px;letter-spacing:1px;color:var(--muted);font-weight:700;padding:4px 10px 8px}
.side a{display:flex;align-items:center;justify-content:space-between;padding:11px 12px;border-radius:10px;font-size:14px;font-weight:600;color:#374151;transition:.2s;text-decoration:none}
.side a .tx{flex:1}
.side a .n{font-size:12px;color:#9aa7b8;font-weight:600;margin-left:8px}
.side a:hover{background:var(--brand-l);color:var(--brand)}
.side a.active{background:var(--brand);color:#fff}
.side a.active .n{color:rgba(255,255,255,.8)}

/* ---------- 分类分组 ---------- */
.group{margin-bottom:38px;scroll-margin-top:88px}
.group-head{display:flex;align-items:baseline;gap:12px;margin-bottom:16px;padding-bottom:10px;border-bottom:2px solid var(--line)}
.group-head h2{font-size:21px;font-weight:800;color:var(--brand-d);margin:0}
.group-head span{font-size:13px;color:var(--muted)}

/* ---------- 视频卡片网格 ---------- */
.vgrid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.vcard{background:#fff;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;transition:.25s;display:flex;flex-direction:column;text-decoration:none;color:inherit}
.vcard:hover{transform:translateY(-4px);box-shadow:var(--shadow);border-color:transparent}
.vthumb{position:relative;aspect-ratio:16/9;overflow:hidden;background:#0f1f38}
.vthumb svg{width:100%;height:100%;display:block}
.vthumb .play{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);width:48px;height:48px;border-radius:50%;background:rgba(255,255,255,.92);display:grid;place-items:center;transition:.2s}
.vthumb .play::after{content:"";border-style:solid;border-width:9px 0 9px 15px;border-color:transparent transparent transparent var(--brand);margin-left:3px}
.vcard:hover .vthumb .play{transform:translate(-50%,-50%) scale(1.12);background:#fff}
.vthumb .dur{position:absolute;right:8px;bottom:8px;background:rgba(0,0,0,.6);color:#fff;font-size:11px;padding:2px 8px;border-radius:6px}
.vbody{padding:13px 15px 15px;flex:1;display:flex;flex-direction:column}
.vbody .vcat{font-size:11px;color:var(--muted);font-weight:700;margin-bottom:4px}
.vbody .vt{font-size:14.5px;font-weight:700;color:var(--ink);line-height:1.4}
.vbody .vgo{margin-top:auto;padding-top:10px;font-size:13px;color:var(--brand);font-weight:600}

/* ---------- 可见 FAQ 区块 ---------- */
.v-faq{max-width:860px;margin:0 auto 60px;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px 28px}
.v-faq h2{font-size:21px;font-weight:800;color:var(--brand-d);margin-bottom:14px}
.v-faq details{border-bottom:1px solid var(--line);padding:4px 0}
.v-faq details:last-child{border-bottom:0}
.v-faq summary{cursor:pointer;font-size:15px;font-weight:600;color:var(--ink);padding:12px 0;list-style:none}
.v-faq summary::-webkit-details-marker{display:none}
.v-faq summary::before{content:"＋";color:var(--brand);font-weight:800;margin-right:10px}
.v-faq details[open] summary::before{content:"－"}
.v-faq .a{color:var(--muted);font-size:14px;line-height:1.8;padding:0 0 14px 26px}

/* ---------- 响应式 ---------- */
@media(max-width:980px){
  .vgrid{grid-template-columns:1fr 1fr}
  .hero{grid-template-columns:1fr}
  .hero .hthumb{aspect-ratio:16/9}
}
@media(max-width:820px){
  .layout{grid-template-columns:1fr;gap:20px}
  .side{position:static;display:flex;flex-wrap:wrap;gap:8px;padding:12px}
  .side .search{width:100%}
  .side .s-title{width:100%}
  .side a{width:auto;flex:1 1 40%}
}
@media(max-width:560px){
  .vgrid{grid-template-columns:1fr}
  .v-stats{gap:18px}
}