:root{
  --ink:#16202a; --muted:#657586; --line:#dbe4ec; --bg:#f6f9fb; --card:#fff;
  --accent:#0e7490; --ok:#15803d; --ok-bg:#eaf7ef; --bad:#be123c; --bad-bg:#fdeef1;
  --shadow:0 2px 14px rgba(15,40,60,.09);
}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans SC","PingFang SC",
  "Microsoft YaHei",Roboto,sans-serif;line-height:1.65}
a{color:var(--accent)}
.topbar{background:var(--accent);color:#fff;padding:0 22px;display:flex;align-items:center;
  justify-content:space-between;min-height:54px;position:sticky;top:0;z-index:60;
  box-shadow:0 2px 8px rgba(0,0,0,.22);gap:12px}
.topbar .crumb{font-size:12px;opacity:.8}
.topbar .ttl{font-size:16px;font-weight:700}
.tb-right{display:flex;gap:8px;flex-shrink:0}
.tb-btn{background:rgba(255,255,255,.18);border:1px solid rgba(255,255,255,.34);color:#fff;
  padding:5px 12px;border-radius:6px;font-size:12px;font-weight:700;text-decoration:none;
  white-space:nowrap}
.tb-btn:hover{background:rgba(255,255,255,.32)}

.hero{background:linear-gradient(135deg,#083344 0%,var(--accent) 55%,#22d3ee 130%);
  color:#fff;padding:36px 22px 30px;text-align:center}
.hero h1{margin:0 0 8px;font-size:1.9rem;font-weight:900;letter-spacing:-.01em}
.hero p{margin:0 auto;max-width:640px;font-size:.92rem;opacity:.9}
.hero .stats{display:flex;gap:26px;justify-content:center;flex-wrap:wrap;margin-top:20px}
.hero .stat b{display:block;font-size:1.6rem;font-weight:800}
.hero .stat span{font-size:.68rem;text-transform:uppercase;letter-spacing:.05em;opacity:.75}

.wrap{max-width:1080px;margin:0 auto;padding:26px 18px 70px}
.note{background:var(--card);border:1px solid var(--line);border-left:4px solid var(--accent);
  border-radius:10px;padding:16px 20px;margin-bottom:20px;box-shadow:var(--shadow)}
.note h3{margin:0 0 6px;font-size:.94rem;color:var(--accent)}
.note p{margin:0;font-size:.86rem;color:#4a5a68}

.lv-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:16px}
.lv-card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:20px;
  text-decoration:none;color:inherit;display:block;transition:.18s;position:relative;overflow:hidden}
.lv-card::before{content:'';position:absolute;inset:0 0 auto 0;height:4px;background:var(--c)}
.lv-card:hover{transform:translateY(-2px);box-shadow:0 8px 22px rgba(0,0,0,.13)}
.lv-badge{display:inline-block;background:var(--c);color:#fff;font-size:.68rem;font-weight:800;
  padding:2px 10px;border-radius:9px;letter-spacing:.04em}
.lv-name{font-size:1.15rem;font-weight:800;margin:9px 0 3px}
.lv-cn{font-size:.9rem;color:var(--muted)}
.lv-desc{font-size:.81rem;color:var(--muted);margin:9px 0 12px}
.lv-meta{display:flex;gap:8px;flex-wrap:wrap;font-size:.72rem}
.chip{background:#eef4f8;border:1px solid var(--line);border-radius:6px;padding:2px 9px;font-weight:600}
.chip.audio{background:#e8f6ef;border-color:#bfe3cf;color:var(--ok)}

.paper-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:14px}
.paper-card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:17px;
  text-decoration:none;color:inherit;transition:.18s;display:block}
.paper-card:hover{transform:translateY(-2px);box-shadow:0 7px 20px rgba(0,0,0,.12)}
.paper-code{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:1.02rem;font-weight:800}
.paper-sub{font-size:.78rem;color:var(--muted);margin-top:5px}
.paper-tags{margin-top:10px;display:flex;gap:6px;flex-wrap:wrap;font-size:.7rem}

h2.sec{font-size:1.1rem;font-weight:800;color:var(--accent);margin:30px 0 13px;
  padding-bottom:8px;border-bottom:2px solid var(--line)}

/* ---------- paper page ---------- */
.player{position:sticky;top:54px;z-index:50;background:var(--card);border:1px solid var(--line);
  border-radius:12px;padding:13px 16px;margin-bottom:18px;box-shadow:var(--shadow)}
.player .row{display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.player audio{flex:1;min-width:230px;height:38px}
.player .lbl{font-size:.78rem;font-weight:700;color:var(--muted);white-space:nowrap}
.spd{display:flex;gap:5px}
.spd button{border:1px solid var(--line);background:#f2f7fa;border-radius:6px;padding:3px 9px;
  font-size:.74rem;font-weight:700;cursor:pointer;color:var(--ink)}
.spd button.on{background:var(--accent);color:#fff;border-color:var(--accent)}

.panel{background:var(--card);border:1px solid var(--line);border-radius:12px;margin-bottom:16px;
  box-shadow:var(--shadow);overflow:hidden}
.panel>summary{cursor:pointer;padding:13px 18px;font-weight:800;font-size:.92rem;
  background:#eef4f8;list-style:none;display:flex;align-items:center;gap:9px}
.panel>summary::-webkit-details-marker{display:none}
.panel>summary::before{content:'▸';transition:.15s;color:var(--accent)}
.panel[open]>summary::before{transform:rotate(90deg)}
.panel .body{padding:16px 18px}
.transcript{white-space:pre-wrap;font-size:.9rem;line-height:1.95;color:#22303c}

.pages img{width:100%;height:auto;display:block;border:1px solid var(--line);border-radius:9px;
  margin-bottom:13px;background:#fff}

.sheet{display:grid;grid-template-columns:repeat(auto-fill,minmax(146px,1fr));gap:9px}
.q{border:1px solid var(--line);border-radius:8px;padding:7px 9px;background:#fbfdfe}
.q .n{font-size:.72rem;font-weight:800;color:var(--muted);margin-bottom:5px}
.q .opts{display:flex;gap:4px;flex-wrap:wrap}
.q .opts button{flex:1;min-width:28px;border:1px solid var(--line);background:#fff;border-radius:5px;
  padding:5px 0;font-size:.8rem;font-weight:700;cursor:pointer;color:var(--ink)}
.q .opts button.sel{background:var(--accent);color:#fff;border-color:var(--accent)}
.q input{width:100%;border:1px solid var(--line);border-radius:5px;padding:5px 7px;font-size:.82rem;
  font-family:inherit}
.q.right{background:var(--ok-bg);border-color:#bfe3cf}
.q.wrong{background:var(--bad-bg);border-color:#f3c2ce}
.q .truth{font-size:.72rem;font-weight:700;color:var(--bad);margin-top:5px}

.blockhead{display:flex;align-items:baseline;gap:10px;margin:20px 0 10px;flex-wrap:wrap}
.blockhead .bn{font-weight:800;font-size:.93rem}
.blockhead .br{font-size:.75rem;color:var(--muted)}

.bar{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:20px 0 4px}
.btn{border:none;border-radius:8px;padding:10px 20px;font-size:.87rem;font-weight:800;cursor:pointer}
.btn.primary{background:var(--accent);color:#fff}
.btn.ghost{background:#eef4f8;color:var(--ink);border:1px solid var(--line)}
.score{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:16px 18px;
  margin:16px 0;box-shadow:var(--shadow);display:none}
.score.on{display:block}
.score h3{margin:0 0 10px;font-size:1rem}
.score table{width:100%;border-collapse:collapse;font-size:.86rem}
.score td,.score th{padding:6px 8px;border-bottom:1px solid var(--line);text-align:left}
.score .big{font-size:1.5rem;font-weight:900;color:var(--accent)}

.written li{margin-bottom:8px;font-size:.9rem}
.footer{background:var(--accent);color:rgba(255,255,255,.85);text-align:center;padding:24px;
  font-size:.79rem}
.footer a{color:#a5f3fc;text-decoration:none}
@media(max-width:680px){
  .hero h1{font-size:1.42rem}
  .wrap{padding:18px 12px 50px}
  .sheet{grid-template-columns:repeat(auto-fill,minmax(118px,1fr))}
  .player{top:54px}
}