:root{
  --bg:#0f1220; --card:#fff; --ink:#1f2733; --muted:#5b6478; --line:#e7eaf3;
  --brand:#3b5bdb; --brand2:#7048e8; --gold:#e8a33d; --soft:#f4f6fb; --pt:#eef2ff;
  --good:#2f9e44; --goodbg:#ebfbee; --goodline:#b2f2bb;
  --bad:#e03131; --badbg:#fff5f5; --badline:#ffc9c9; --topH:54px;
}
*{box-sizing:border-box}
html,body{height:100%}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei","Hiragino Sans GB",Segoe UI,Roboto,Arial,sans-serif;
  color:var(--ink);background:var(--soft);line-height:1.7;-webkit-font-smoothing:antialiased}
a{color:var(--brand);text-decoration:none;cursor:pointer}
.hide{display:none!important}
.btn{cursor:pointer;border:none;border-radius:10px;font-weight:600;font-size:15px;padding:11px 18px;
  background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff;transition:.15s}
.btn:hover{opacity:.92}.btn:disabled{opacity:.45;cursor:not-allowed}
.btn.block{width:100%}
.btn.ghost{background:#fff;color:var(--brand);border:1px solid var(--line)}
.btn.sm{padding:7px 13px;font-size:13px;border-radius:8px}
.spin{display:inline-block;width:15px;height:15px;border:2px solid rgba(255,255,255,.5);border-top-color:#fff;border-radius:50%;animation:sp .7s linear infinite;vertical-align:-2px}
@keyframes sp{to{transform:rotate(360deg)}}
.boot{position:fixed;inset:0;display:flex;align-items:center;justify-content:center;color:var(--muted);background:var(--soft)}

/* ---------- auth ---------- */
.auth-wrap{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px;
  background:radial-gradient(1100px 460px at 18% -8%,#27306a 0,transparent 60%),linear-gradient(160deg,#0f1220,#1b2143)}
.auth-card{width:100%;max-width:430px;background:#fff;border-radius:18px;padding:30px 28px;box-shadow:0 18px 50px rgba(8,12,30,.35)}
.auth-brand{font-weight:800;font-size:22px}.auth-brand span{color:var(--gold)}
.auth-lead{color:var(--muted);font-size:14px;margin:6px 0 18px}
.tabs{display:flex;background:var(--soft);border-radius:10px;padding:4px;margin-bottom:18px}
.tabs button{flex:1;border:none;background:none;padding:9px;border-radius:8px;cursor:pointer;font-weight:600;color:var(--muted)}
.tabs button.on{background:#fff;color:var(--ink);box-shadow:0 1px 4px rgba(0,0,0,.08)}
.field{margin-bottom:13px}
.field label{display:block;font-size:13px;font-weight:600;color:#39435c;margin-bottom:6px}
.field input{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:10px;font-size:15px;outline:none}
.field input:focus{border-color:var(--brand);box-shadow:0 0 0 3px rgba(59,91,219,.12)}
.msg{font-size:13.5px;padding:10px 12px;border-radius:9px;margin-bottom:13px}
.msg.err{background:var(--badbg);color:var(--bad);border:1px solid var(--badline)}
.msg.ok{background:var(--goodbg);color:var(--good);border:1px solid var(--goodline)}
.auth-hint{text-align:center;color:#9aa3bb;font-size:12px;margin-top:14px}

/* ---------- topbar ---------- */
.topbar{height:var(--topH);position:sticky;top:0;z-index:50;background:rgba(15,18,32,.96);backdrop-filter:blur(8px);
  color:#fff;display:flex;align-items:center;gap:12px;padding:0 16px;border-bottom:1px solid rgba(255,255,255,.08)}
.topbar .brand{font-weight:800}.topbar .brand .accent{color:var(--gold)}
.topbar .brand-sub{color:#aeb6cc;font-size:13px}
.tabs-nav{display:flex;gap:2px;margin-left:14px}
.tabs-nav a{color:#cfd6ea;font-size:14px;padding:7px 13px;border-radius:9px;white-space:nowrap}
.tabs-nav a:hover{background:rgba(255,255,255,.08);text-decoration:none}
.tabs-nav a.on{background:rgba(255,255,255,.14);color:#fff;font-weight:600}
.topbar .spacer{flex:1}
.topbar .who{font-size:13px;color:#aeb6cc;white-space:nowrap}
.menu-toggle{display:none;background:none;border:1px solid rgba(255,255,255,.25);color:#fff;border-radius:8px;padding:5px 11px;cursor:pointer}
.scrim{display:none}

.content{max-width:1080px;margin:0 auto;padding:26px 20px 70px}
.pane{display:none}.pane.on{display:block;animation:fade .2s}
@keyframes fade{from{opacity:0;transform:translateY(5px)}to{opacity:1;transform:none}}

.card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:22px 24px;margin-bottom:18px;box-shadow:0 1px 3px rgba(20,30,60,.04)}
.card h2{margin:0 0 4px;font-size:21px}
.card h3{margin:0 0 12px;font-size:16px}
.muted{color:var(--muted)}
.pagehead{margin:2px 0 18px}
.pagehead h1{font-size:24px;margin:0 0 2px}
.pagehead p{margin:0;color:var(--muted);font-size:14px}

/* profile */
.kv{display:grid;grid-template-columns:120px 1fr;gap:10px 16px;font-size:14.5px}
.kv .k{color:var(--muted)}
.stat-row{display:flex;gap:12px;flex-wrap:wrap;margin-top:6px}
.stat{background:var(--soft);border:1px solid var(--line);border-radius:12px;padding:12px 18px;min-width:120px}
.stat b{display:block;font-size:24px;color:var(--brand)}
.stat span{font-size:13px;color:var(--muted)}
.htable{width:100%;border-collapse:collapse;font-size:13.5px;margin-top:6px}
.htable th,.htable td{text-align:left;padding:8px 10px;border-bottom:1px solid var(--line)}
.htable th{color:var(--muted);font-weight:600}
.tag{display:inline-block;padding:2px 10px;border-radius:999px;font-size:12px;font-weight:700}
.tag.pass{background:var(--goodbg);color:var(--good)}.tag.fail{background:var(--badbg);color:var(--bad)}
.adminbar{background:#fff8ee;border:1px solid #f0d9b5;border-radius:12px;padding:12px 16px;margin-bottom:16px;font-size:13.5px;color:#6b4a12;display:flex;align-items:center;gap:12px;flex-wrap:wrap}

/* course reader */
.reader{display:grid;grid-template-columns:260px 1fr;gap:20px;align-items:start}
.lesson-toc{position:sticky;top:calc(var(--topH) + 16px);max-height:calc(100vh - var(--topH) - 40px);overflow:auto;
  background:#fff;border:1px solid var(--line);border-radius:14px;padding:12px}
.lesson-toc .sec{font-weight:700;color:var(--brand);font-size:12px;margin:12px 6px 4px}
.lesson-toc a{display:flex;gap:8px;padding:6px 8px;border-radius:8px;color:var(--muted);font-size:13px}
.lesson-toc a:hover{background:var(--soft);text-decoration:none}
.lesson-toc a.on{background:var(--pt);color:var(--brand);font-weight:600}
.lesson-toc .tn{font-size:11px;color:#9aa3bb;min-width:24px}
.lesson-body{background:#fff;border:1px solid var(--line);border-radius:16px;padding:26px 30px;min-width:0}
.lesson-body .kicker{color:var(--brand2);font-weight:700;font-size:13px;letter-spacing:1px;margin-bottom:6px}
.lesson-body h2{margin:0 0 14px;font-size:25px}
.points{background:var(--pt);border:1px solid #dfe6fb;border-radius:12px;padding:12px 16px;margin-bottom:20px}
.points-tag{font-size:12px;font-weight:700;color:var(--brand);letter-spacing:1px;margin-bottom:5px}
.points ul{margin:0;padding-left:1.1em}.points li{padding:3px 0;font-size:14px;color:#3c4660}
.prose{font-size:16.5px;color:#26303f;line-height:1.9}
.prose p{margin:0 0 1em}
.prose ul,.prose ol{margin:0 0 1em;padding-left:1.3em}
.prose strong{color:#15233f;font-weight:700;background:linear-gradient(transparent 62%,#fde7c4 62%)}
.prose blockquote{font-size:15.5px}.prose blockquote strong{background:none}
.prose code{background:#eef1f8;border:1px solid #e1e6f2;border-radius:5px;padding:1px 6px;font-size:.9em}
.stab{border-collapse:collapse;width:100%;margin:12px 0;font-size:13.5px}
.stab th,.stab td{border:1px solid #d7def3;padding:8px 11px;text-align:left;vertical-align:top}
.stab th{background:#e3e9fc;color:#2b3a73;font-weight:700}
.ext{margin-top:22px;background:#fff8ee;border:1px solid #f0d9b5;border-radius:13px;padding:16px 18px}
.ext-tag{display:inline-block;background:var(--gold);color:#241a06;font-weight:700;font-size:11px;letter-spacing:1px;padding:3px 10px;border-radius:999px;margin-bottom:7px}
.ext h3{margin:.1em 0 .3em;font-size:17px;color:#6b4a12}.ext p,.ext li{font-size:14px;color:#4a3a20;line-height:1.75}
.ext b{color:#7a4f10}
.refs{margin-top:10px;border-top:1px dashed #f0d9b5;padding-top:8px}
.refs-tag{font-weight:700;font-size:11px;color:#8a6a2a;letter-spacing:1px;margin-bottom:4px}
.refs ul{list-style:none;margin:0;padding:0}.refs li{padding:3px 0 3px 16px;position:relative;font-size:13px}
.refs li::before{content:"↗";position:absolute;left:0;color:var(--brand)}
.lesson-nav{display:flex;gap:10px;margin-top:22px;border-top:1px solid var(--line);padding-top:16px}
.lesson-nav .spacer{flex:1}

/* quiz */
.qprogress{display:flex;align-items:center;gap:14px;margin-bottom:16px}
.qbar{flex:1;height:9px;background:#e6eaf4;border-radius:999px;overflow:hidden}
.qbar>i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--gold),var(--brand2));transition:.3s}
.qcount{font-size:13px;color:var(--muted);font-weight:600;white-space:nowrap}
.qtype{display:inline-block;font-size:12px;font-weight:700;letter-spacing:1px;padding:3px 11px;border-radius:999px;margin-bottom:12px}
.qtype.single{background:var(--pt);color:var(--brand)}.qtype.multi{background:#f3effe;color:var(--brand2)}
.qtext{font-size:18px;font-weight:600;line-height:1.5;margin-bottom:18px}
.opts{display:flex;flex-direction:column;gap:10px}
.opt{display:flex;align-items:flex-start;gap:12px;padding:13px 15px;border:1.5px solid var(--line);border-radius:12px;cursor:pointer;transition:.13s;background:#fff}
.opt:hover{border-color:#c3ccea}.opt.sel{border-color:var(--brand);background:#f3f6ff}
.opt .mark{flex:none;width:23px;height:23px;border:2px solid #c3ccea;display:flex;align-items:center;justify-content:center;font-weight:700;color:var(--muted);font-size:13px}
.opt.single .mark{border-radius:50%}.opt.multi .mark{border-radius:7px}
.opt.sel .mark{border-color:var(--brand);background:var(--brand);color:#fff}
.opt.locked{cursor:default}
.opt.correct{border-color:var(--good);background:var(--goodbg)}.opt.correct .mark{border-color:var(--good);background:var(--good);color:#fff}
.opt.wrong{border-color:var(--bad);background:var(--badbg)}.opt.wrong .mark{border-color:var(--bad);background:var(--bad);color:#fff}
.opt .badge{margin-left:auto;font-size:12px;font-weight:700;white-space:nowrap}
.opt.correct .badge{color:var(--good)}.opt.wrong .badge{color:var(--bad)}
.feedback{margin-top:16px;border-radius:12px;padding:14px 16px;font-size:14.5px;border:1px solid}
.feedback.right{background:var(--goodbg);border-color:var(--goodline)}.feedback.wrong{background:var(--badbg);border-color:var(--badline)}
.feedback .fh{font-weight:700;font-size:15px;margin-bottom:5px}.feedback.right .fh{color:var(--good)}.feedback.wrong .fh{color:var(--bad)}
.feedback .ans{margin-top:7px;font-size:13px;color:var(--muted)}
.qfoot{margin-top:20px;display:flex;gap:12px;align-items:center}.qfoot .spacer{flex:1}
.scorewrap{margin:6px auto 16px;width:160px;height:160px;border-radius:50%;display:flex;flex-direction:column;align-items:center;justify-content:center;color:#fff}
.scorewrap.pass{background:radial-gradient(circle at 30% 25%,#51cf66,#2f9e44)}.scorewrap.fail{background:radial-gradient(circle at 30% 25%,#ff8787,#e03131)}
.scorewrap .pct{font-size:44px;font-weight:800;line-height:1}.scorewrap .frac{font-size:15px;opacity:.92;margin-top:5px}
.review .ritem{display:flex;gap:12px;padding:11px 0;border-bottom:1px dashed var(--line)}
.review .ri{flex:none;width:25px;height:25px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:14px;font-weight:700;color:#fff}
.review .ri.c{background:var(--good)}.review .ri.w{background:var(--bad)}
.review .rq{font-size:14px;font-weight:600;margin-bottom:2px}.review .rex{font-size:13px;color:var(--muted)}

/* library */
.lib-list{display:grid;gap:10px}
.lib-item{display:flex;align-items:center;gap:14px;background:#fff;border:1px solid var(--line);border-radius:12px;padding:14px 16px}
.lib-ico{width:40px;height:40px;border-radius:10px;background:var(--pt);display:flex;align-items:center;justify-content:center;font-size:20px;flex:none}
.lib-meta{flex:1;min-width:0}.lib-meta .t{font-weight:600}.lib-meta .d{font-size:13px;color:var(--muted)}
.dropzone{border:2px dashed #cdd6ee;border-radius:12px;padding:18px;text-align:center;color:var(--muted);font-size:14px;background:#fbfcff}

/* assistant */
.chat{display:flex;flex-direction:column;height:calc(100vh - var(--topH) - 120px);min-height:420px;
  background:#fff;border:1px solid var(--line);border-radius:16px;overflow:hidden}
.chat-head{padding:12px 18px;border-bottom:1px solid var(--line);display:flex;align-items:center;gap:10px;font-size:14px}
.chat-head .dot{width:9px;height:9px;border-radius:50%;background:var(--good)}
.chat-log{flex:1;overflow:auto;padding:18px;display:flex;flex-direction:column;gap:14px}
.bubble{max-width:80%;padding:11px 15px;border-radius:14px;font-size:14.5px;line-height:1.7;white-space:pre-wrap;word-break:break-word}
.bubble.user{align-self:flex-end;background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff;border-bottom-right-radius:4px}
.bubble.ai{align-self:flex-start;background:var(--soft);border:1px solid var(--line);border-bottom-left-radius:4px}
.bubble .src{margin-top:8px;font-size:12px;color:var(--muted);border-top:1px dashed var(--line);padding-top:6px}
.chat-hint{align-self:center;color:#9aa3bb;font-size:13px;text-align:center;max-width:460px}
.chat-in{display:flex;gap:10px;padding:12px;border-top:1px solid var(--line);background:#fff}
.chat-in textarea{flex:1;resize:none;border:1px solid var(--line);border-radius:10px;padding:11px 13px;font-size:14.5px;font-family:inherit;outline:none;max-height:120px}
.chat-in textarea:focus{border-color:var(--brand)}
.suggest{display:flex;gap:8px;flex-wrap:wrap;margin-top:4px}
.suggest button{background:#fff;border:1px solid var(--line);border-radius:999px;padding:6px 12px;font-size:13px;color:var(--brand);cursor:pointer}
.suggest button:hover{background:var(--pt)}

@media (max-width:820px){
  .tabs-nav{position:fixed;top:var(--topH);left:0;bottom:0;width:240px;flex-direction:column;background:#11142a;
    padding:14px 10px;gap:4px;transform:translateX(-100%);transition:.25s;z-index:45}
  .tabs-nav.open{transform:none}
  .tabs-nav a{font-size:15px;padding:11px 14px}
  .menu-toggle{display:inline-block}
  .scrim.show{display:block;position:fixed;inset:var(--topH) 0 0 0;background:rgba(8,10,22,.5);z-index:44}
  .brand-sub{display:none}
  .reader{grid-template-columns:1fr}
  .lesson-toc{position:static;max-height:none;margin-bottom:14px}
  .bubble{max-width:92%}
}

/* 词汇库 */
.gloss-tools{position:sticky;top:var(--topH);z-index:5;background:var(--soft);padding:6px 0 10px;margin-bottom:6px}
.gloss-search{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:10px;font-size:15px;outline:none;background:#fff}
.gloss-search:focus{border-color:var(--brand)}
.gloss-cats{display:flex;flex-wrap:nowrap;gap:7px;margin-top:10px;overflow-x:auto;overflow-y:hidden;padding-bottom:6px;-webkit-overflow-scrolling:touch;scrollbar-width:thin;scroll-snap-type:x proximity}
.gloss-cats::-webkit-scrollbar{height:6px}
.gloss-cats::-webkit-scrollbar-thumb{background:#cfd6e6;border-radius:3px}
.gloss-cats button{flex:0 0 auto;white-space:nowrap;scroll-snap-align:start;cursor:pointer;border:1px solid var(--line);background:#fff;color:var(--muted);border-radius:999px;padding:5px 12px;font-size:13px;font-weight:600}
.gloss-cats button.on{background:var(--pt);color:var(--brand);border-color:#c3cffb}
.gloss-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:12px}
.gloss-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:14px 16px;box-shadow:0 1px 3px rgba(20,30,60,.04)}
.gloss-term{font-weight:700;font-size:16px;color:var(--ink);display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.gloss-en{font-weight:500;font-size:13px;color:var(--muted)}
.gloss-cat{margin-left:auto;font-size:11px;font-weight:600;color:var(--brand);background:var(--pt);border-radius:6px;padding:2px 8px}
.gloss-def{margin-top:7px;font-size:14px;line-height:1.6;color:#2b3342}
.gloss-cmp{margin-top:9px;font-size:13px;line-height:1.6;color:#5a4310;background:#fff8ee;border-left:3px solid var(--gold);border-radius:0 8px 8px 0;padding:8px 11px}
.gloss-cmp b{color:#7a5a12}
.gloss-more{grid-column:1/-1;text-align:center;color:var(--muted);font-size:13px;padding:14px}
/* 词汇库 · 目录视图 */
.gloss-dir{display:block}
.gloss-sec{margin-bottom:18px}
.gloss-sech{font-weight:700;font-size:15px;color:var(--ink);padding:9px 0;border-bottom:2px solid var(--pt);margin-bottom:11px;cursor:pointer;display:flex;align-items:baseline;gap:8px}
.gloss-sech:hover{color:var(--brand)}
.gloss-sech.static{cursor:default;grid-column:1/-1}
.gloss-sech span{color:var(--muted);font-weight:500;font-size:13px}
.gloss-terms{display:flex;flex-wrap:wrap;gap:7px}
.gloss-tchip{cursor:pointer;border:1px solid var(--line);background:#fff;color:var(--ink);border-radius:8px;padding:5px 11px;font-size:13.5px;transition:.12s}
.gloss-tchip:hover{background:var(--pt);border-color:#c3cffb;color:var(--brand)}
@media(max-width:560px){ .gloss-list{grid-template-columns:1fr} }

/* 导航分组 */
.nav-sep{align-self:center;width:1px;height:16px;background:rgba(255,255,255,.16);margin:0 5px;overflow:hidden;text-indent:-999px;flex:0 0 auto}
/* 学习首页 · 仪表盘 */
.dash-sec{font-size:13px;font-weight:700;color:var(--muted);margin:22px 2px 12px;letter-spacing:.3px}
.dash-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:13px}
.dash-card{display:flex;align-items:center;gap:13px;background:#fff;border:1px solid var(--line);border-radius:14px;padding:16px 18px;cursor:pointer;box-shadow:0 1px 3px rgba(20,30,60,.04);transition:.14s}
.dash-card:hover{border-color:#c3cffb;box-shadow:0 6px 18px rgba(40,60,120,.10);transform:translateY(-1px)}
.dash-ic{font-size:26px;line-height:1;flex:0 0 auto}
.dash-body{flex:1;min-width:0}
.dash-t{font-weight:700;font-size:16px;color:var(--ink)}
.dash-d{font-size:13px;color:var(--muted);margin-top:3px}
.dash-arrow{color:#c3cce0;font-size:18px;font-weight:700}
.dash-card:hover .dash-arrow{color:var(--brand)}
@media (max-width:820px){
  .nav-sep{align-self:stretch;width:auto;height:auto;background:none;text-indent:0;color:#7f88a3;font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.6px;padding:12px 14px 4px;margin:0}
  .dash-grid{grid-template-columns:1fr}
}

/* =================== React 版增强（动效 / 交互 / 视觉） =================== */
.splash{position:fixed;inset:0;display:flex;align-items:center;justify-content:center;background:var(--soft)}
.splash .spin{width:30px;height:30px;border-width:3px;border-color:rgba(59,91,219,.2);border-top-color:var(--brand)}
.cfgwarn{max-width:560px;margin:80px auto;background:#fff;border:1px solid var(--line);border-radius:14px;padding:24px;color:var(--ink);line-height:1.7}
/* 视图切换动画 */
.view-anim{animation:viewIn .28s ease}
@keyframes viewIn{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}
.auth-card.pop{animation:pop .32s cubic-bezier(.2,.8,.3,1.2)}
@keyframes pop{from{opacity:0;transform:translateY(10px) scale(.98)}to{opacity:1;transform:none}}
/* Toast 通知 */
.toast-host{position:fixed;left:50%;bottom:26px;transform:translateX(-50%);display:flex;flex-direction:column;gap:8px;z-index:200;align-items:center;pointer-events:none}
.toast{color:#fff;padding:10px 18px;border-radius:10px;font-size:14px;font-weight:500;box-shadow:0 10px 28px rgba(8,12,30,.32);background:#1b2143;animation:toastIn .25s ease}
.toast.ok{background:linear-gradient(135deg,#2f9e44,#37b24d)}
.toast.err{background:linear-gradient(135deg,#e03131,#f03e3e)}
@keyframes toastIn{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}
/* 链接 / 输入 */
.lnk{color:var(--brand);font-size:13px;cursor:pointer;margin-left:6px}
.lnk:hover{text-decoration:underline}
.field-in{width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:10px;margin-top:10px;font-size:14px;outline:none}
.field-in:focus{border-color:var(--brand)}
/* 纯文本气泡（想法陪练保留换行） */
.bubble.plain{white-space:pre-wrap}
/* 打字指示 */
.bubble.typing{display:inline-flex;gap:5px;align-items:center;padding:15px 16px}
.bubble.typing span{width:7px;height:7px;border-radius:50%;background:#aab2c8;display:inline-block;animation:typ 1s infinite}
.bubble.typing span:nth-child(2){animation-delay:.15s}
.bubble.typing span:nth-child(3){animation-delay:.3s}
@keyframes typ{0%,60%,100%{opacity:.3;transform:translateY(0)}30%{opacity:1;transform:translateY(-4px)}}
/* 视觉提升：按钮/卡片/选项 微交互 */
.btn{transition:transform .12s,box-shadow .14s,filter .12s}
.btn:hover:not(:disabled){transform:translateY(-1px);box-shadow:0 7px 18px rgba(59,91,219,.30)}
.btn.ghost:hover:not(:disabled){box-shadow:0 6px 16px rgba(20,30,60,.12)}
.btn:active:not(:disabled){transform:translateY(0)}
.stat{transition:transform .15s,box-shadow .15s}
.stat:hover{transform:translateY(-2px);box-shadow:0 6px 16px rgba(20,30,60,.08)}
.opt{transition:border-color .12s,background .12s,transform .08s}
.opt:hover:not(.locked){border-color:#c3cffb;background:var(--pt)}
.opt:active:not(.locked){transform:scale(.995)}
.bubble{animation:bubbleIn .2s ease}
@keyframes bubbleIn{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}

/* =================== 课程选择 + 阅读器顶部 =================== */
.course-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}
.course-card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:22px 22px 20px 26px;cursor:pointer;box-shadow:0 1px 3px rgba(20,30,60,.04);transition:transform .16s,box-shadow .16s,border-color .16s;position:relative;overflow:hidden}
.course-card::before{content:"";position:absolute;left:0;top:0;bottom:0;width:5px;background:linear-gradient(var(--brand),var(--brand2))}
.course-card:hover{transform:translateY(-3px);box-shadow:0 12px 30px rgba(40,60,120,.13);border-color:#c3cffb}
.course-no{font-size:13px;font-weight:700;color:var(--brand);margin-bottom:6px}
.course-title{font-size:20px;font-weight:800;color:var(--ink);line-height:1.3}
.course-date{font-size:13px;color:var(--muted);margin-top:8px}
.course-desc{font-size:13.5px;color:#4b5566;line-height:1.6;margin-top:10px}
.course-go{margin-top:14px;font-weight:700;color:var(--brand)}
.course-card.soon{cursor:default;opacity:.65;background:var(--soft)}
.course-card.soon::before{background:#ccd3e6}
.course-card.soon:hover{transform:none;box-shadow:0 1px 3px rgba(20,30,60,.04);border-color:var(--line)}
.reader-top{display:flex;align-items:center;gap:12px;margin-bottom:14px;flex-wrap:wrap}
.reader-top .lnk{margin-left:0;font-size:14px}
.reader-course{font-weight:700;color:var(--ink)}

/* =================== AI 问答历史 =================== */
.chat-head .spacer{flex:1}
.chat-hbtn{background:var(--soft);border:1px solid var(--line);color:var(--brand);border-radius:8px;padding:4px 11px;font-size:12.5px;font-weight:600;cursor:pointer;transition:.12s;white-space:nowrap}
.chat-hbtn:hover{background:var(--pt);border-color:#c3cffb}
.hist-list{display:flex;flex-direction:column;gap:8px}
.hist-item{background:#fff;border:1px solid var(--line);border-radius:12px;padding:12px 14px;cursor:pointer;transition:.12s}
.hist-item:hover{border-color:#c3cffb;box-shadow:0 4px 12px rgba(40,60,120,.08);transform:translateY(-1px)}
.hist-q{font-weight:600;color:var(--ink);font-size:14.5px;line-height:1.5}
.hist-row{display:flex;gap:10px;align-items:center;margin-top:6px;min-width:0}
.hist-meta{font-size:12px;color:var(--muted);flex:0 0 auto}
.hist-prev{font-size:12.5px;color:var(--muted);overflow:hidden;white-space:nowrap;text-overflow:ellipsis;min-width:0}
.hist-detail .hist-meta{margin-bottom:8px}

/* 历史：分类标签 + 删除 */
.kind-tag{display:inline-block;font-size:11px;font-weight:700;border-radius:6px;padding:1px 7px;margin-right:7px;vertical-align:middle}
.kind-tag.chat{background:var(--pt);color:var(--brand)}
.kind-tag.advise{background:#fff3e0;color:#b8650f}
.hist-del{background:none;border:1px solid var(--line);color:var(--bad);border-radius:7px;padding:3px 9px;font-size:12px;cursor:pointer;flex:0 0 auto}
.hist-del:hover{background:var(--badbg);border-color:var(--badline)}