:root{
  --bg:#f4f6fb;--card:#fff;--text:#1f2937;--muted:#6b7280;--line:#e5e7eb;
  --brand:#2a5298;--brand-d:#1e3c72;--ok:#16a34a;--ok-bg:#ecfdf5;--bad:#dc2626;--bad-bg:#fef2f2;
  --warn:#d97706;--chip:#eef2ff;--radius:12px;
}
@media(prefers-color-scheme:dark){
  :root{--bg:#0f1420;--card:#192032;--text:#e5e7eb;--muted:#9ca3af;--line:#2a3350;
    --brand:#6ea0ff;--brand-d:#274a8f;--ok:#4ade80;--ok-bg:#12301f;--bad:#f87171;--bad-bg:#3a1a1a;--chip:#222c4a}
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:"PingFang SC","Microsoft YaHei",system-ui,sans-serif;background:var(--bg);color:var(--text);line-height:1.6;-webkit-text-size-adjust:100%}
#app{}
.boot{padding:40px;text-align:center;color:var(--muted)}
button{font:inherit;cursor:pointer;border:1px solid var(--line);background:var(--card);color:var(--text);border-radius:8px;padding:8px 14px}
button:hover{border-color:var(--brand)}
button.primary{background:var(--brand-d);border-color:var(--brand-d);color:#fff}
button.primary:hover{opacity:.92}
button.ghost{background:transparent}
button:disabled{opacity:.5;cursor:not-allowed}
select{font:inherit;padding:7px 10px;border-radius:8px;border:1px solid var(--line);background:var(--card);color:var(--text)}

.top{background:linear-gradient(135deg,#1e3c72,#2a5298);color:#fff;padding:22px 18px 18px}
.top h1{font-size:22px;letter-spacing:1px}
.top p{opacity:.85;font-size:13px;margin-top:4px}
.top .row{display:flex;align-items:center;gap:10px}
.top .back{background:rgba(255,255,255,.18);border:none;color:#fff;padding:5px 10px}
.main{padding:16px}
.card{background:var(--card);border-radius:var(--radius);padding:16px;margin-bottom:14px;box-shadow:0 1px 8px rgba(0,0,0,.06)}
.card h2{font-size:16px;margin-bottom:10px;padding-bottom:8px;border-bottom:2px solid var(--brand)}
.muted{color:var(--muted);font-size:13px}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(130px,1fr));gap:10px}
.subj{text-align:left;padding:12px;border-radius:10px}
.subj b{font-size:18px;display:block}
.bar{height:6px;background:var(--line);border-radius:3px;margin-top:8px;overflow:hidden}
.bar i{display:block;height:100%;background:var(--brand)}
.row{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.chip{display:inline-block;font-size:12px;padding:1px 9px;border-radius:99px;background:var(--chip);color:var(--brand)}
.chip.weak{background:var(--bad-bg);color:var(--bad)}
.list>.item{display:flex;justify-content:space-between;align-items:center;gap:10px;padding:10px 0;border-bottom:1px solid var(--line)}
.list>.item:last-child{border-bottom:none}

.radar{width:100%;max-width:420px;display:block;margin:0 auto}
.radar .ring{fill:none;stroke:var(--line)}
.radar .spoke{stroke:var(--line)}
.radar .lab{font-size:12px;fill:var(--text)}
.radar .lab.na{fill:var(--muted)}
.radar .s-all{fill:rgba(42,82,152,.18);stroke:var(--brand);stroke-width:2}
.radar .s-batch{fill:rgba(234,88,12,.18);stroke:#ea580c;stroke-width:2}
.radar .dot-all{fill:var(--brand)}
.radar .dot-batch{fill:#ea580c}
.legend{display:flex;gap:14px;justify-content:center;font-size:12px;color:var(--muted);margin-top:4px}
.legend i{display:inline-block;width:10px;height:10px;border-radius:2px;margin-right:4px}

.qhead{display:flex;justify-content:space-between;align-items:center;font-size:13px;color:var(--muted);margin-bottom:8px}
.prog{height:5px;background:var(--line);border-radius:3px;margin-bottom:14px;overflow:hidden}
.prog i{display:block;height:100%;background:var(--brand)}
.stem{font-size:17px;white-space:pre-wrap;margin-bottom:14px}
.opts{display:flex;flex-direction:column;gap:8px}
.opt{display:flex;gap:10px;text-align:left;padding:11px 12px;width:100%;align-items:flex-start}
.opt .k{font-weight:700;min-width:1.4em}
.opt.sel{border-color:var(--brand);box-shadow:0 0 0 2px rgba(42,82,152,.25)}
.opt.right{background:var(--ok-bg);border-color:var(--ok)}
.opt.wrong{background:var(--bad-bg);border-color:var(--bad)}
.fill{width:100%;font:inherit;padding:10px 12px;border-radius:8px;border:1px solid var(--line);background:var(--card);color:var(--text)}
.verdict{margin-top:14px;padding:10px 12px;border-radius:8px;font-weight:600}
.verdict.ok{background:var(--ok-bg);color:var(--ok)}
.verdict.bad{background:var(--bad-bg);color:var(--bad)}
.steps{counter-reset:s;list-style:none;margin-top:6px}
.steps li{counter-increment:s;position:relative;padding:8px 8px 8px 38px;border-left:3px solid var(--brand);background:var(--chip);border-radius:0 8px 8px 0;margin-bottom:6px;animation:in .25s}
.steps li::before{content:counter(s);position:absolute;left:10px;top:8px;width:20px;height:20px;border-radius:50%;background:var(--brand-d);color:#fff;font-size:12px;text-align:center;line-height:20px}
@keyframes in{from{opacity:0;transform:translateY(4px)}to{opacity:1;transform:none}}
.why{margin-top:6px}
.why .w{display:flex;gap:8px;padding:7px 10px;border-radius:8px;margin-bottom:5px;border:1px solid var(--line);font-size:14px}
.why .w.right{background:var(--ok-bg);border-color:var(--ok)}
.why .w.mine{border-style:dashed;border-color:var(--bad)}
.why .w b{min-width:1.4em}
.traps{margin-top:6px;padding:8px 12px;background:#fffbeb;color:#92400e;border-radius:8px;font-size:14px}
@media(prefers-color-scheme:dark){.traps{background:#3b2e10;color:#fcd34d}}
.sec-t{font-size:14px;font-weight:700;margin-top:14px}
.actions{display:flex;gap:8px;margin-top:16px;flex-wrap:wrap}
.stat{display:flex;gap:18px;flex-wrap:wrap;margin-bottom:10px}
.stat div b{display:block;font-size:24px}

/* ===== v2：登录、双端自适应、AI ===== */
#app{max-width:none}
.wrap{max-width:1100px;margin:0 auto;padding:0 16px}
.top{padding:16px 0 14px}
.top .wrap{padding-top:0}
.row.between{justify-content:space-between;flex-wrap:nowrap}
.row.nowrap{flex-wrap:nowrap}
.who{gap:8px;font-size:14px;white-space:nowrap}
.top h1{font-size:20px}
.main{padding-top:16px;padding-bottom:40px}
.cols{display:grid;grid-template-columns:1fr;gap:0 16px;align-items:start}
.qgrid{display:grid;grid-template-columns:1fr;gap:0 16px;align-items:start}
@media(min-width:900px){
  .cols{grid-template-columns:1.1fr 1fr}
  .qgrid.done{grid-template-columns:1fr 1fr}
  .qgrid:not(.done){max-width:720px;margin:0 auto}
  .qgrid.done>div:first-child{position:sticky;top:12px}
  .top h1{font-size:24px}
  .stem{font-size:18px}
}
@media(max-width:520px){
  .top .wrap{padding:0 12px}.main{padding-left:12px;padding-right:12px}
  .who span{max-width:7em;overflow:hidden;text-overflow:ellipsis}
  button{padding:9px 12px}
  .opt{padding:12px}
}
.auth{max-width:440px;margin:10px auto}
.tabs{display:flex;gap:6px;margin-bottom:14px}
.tabs button{flex:1;border-radius:8px}
.tabs button.on{background:var(--brand-d);color:#fff;border-color:var(--brand-d)}
.lab2{display:block;font-size:13px;color:var(--muted);margin:12px 0 4px}
.dice{white-space:nowrap}
.wide{width:100%;margin-top:14px;padding:11px}
.msg{min-height:1.4em;margin-top:8px;font-size:13px}
.msg.ok{color:var(--ok)}.msg.bad{color:var(--bad)}
.pitch{margin-top:18px;padding-top:12px;border-top:1px dashed var(--line);font-size:13px;color:var(--muted)}
.pitch b{color:var(--text)}
.aibox{margin-top:8px;padding:10px 12px;border-radius:8px;background:var(--chip);white-space:pre-wrap;font-size:14px;width:100%}
.aibox.u{background:transparent;border:1px dashed var(--line);color:var(--muted)}
.aibox[hidden]{display:none}
.toast{position:fixed;left:50%;bottom:28px;transform:translateX(-50%);background:#111827;color:#fff;padding:9px 16px;border-radius:99px;font-size:14px;z-index:9;max-width:90vw}
.row .fill{flex:1;min-width:0}

/* ===== v3：侧栏布局 + 要点回忆卡 ===== */
.logo{width:34px;height:34px;border-radius:8px}
.layout{display:flex;min-height:100vh}
.side{width:272px;flex:none;background:var(--card,#fff);border-right:1px solid var(--line);padding:14px 12px;position:sticky;top:0;height:100vh;overflow-y:auto;display:flex;flex-direction:column;gap:10px}
.mainpane{flex:1;min-width:0}
.wrap2{max-width:1100px;margin:0 auto;padding:16px 16px 48px}
.topbar{display:flex;align-items:center;gap:10px;padding:10px 16px;border-bottom:1px solid var(--line);position:sticky;top:0;background:var(--bg,#f4f6f9);z-index:5;justify-content:space-between}
.crumb{flex:1;min-width:0;font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.crumb .sep{margin:0 6px;color:var(--muted)}
.crumb a{color:var(--brand-d);text-decoration:none}
.who em{font-style:normal;color:var(--muted)}
.burger{display:none;padding:6px 10px}
.mask{display:none}
.search{width:100%;padding:8px 10px;border:1px solid var(--line);border-radius:8px;background:transparent;color:inherit}
.tools{display:flex;flex-direction:column;gap:4px}
.tools button{text-align:left;display:flex;flex-direction:column;border-radius:8px;padding:8px 10px}
.tools button span{font-size:12px;color:var(--muted);font-weight:400}
.tools button.on{background:var(--brand-d);color:#fff;border-color:var(--brand-d)}
.tools button.on span{color:#dbe6ff}
.tree{flex:1;overflow-y:auto}
.tree summary{cursor:pointer;display:flex;justify-content:space-between;padding:6px 4px;font-weight:600}
.ni{display:flex;align-items:center;gap:6px;width:100%;text-align:left;border:0;background:transparent;padding:6px 8px;border-radius:6px;font-weight:400}
.ni.on{background:var(--chip);font-weight:600}
.ni .nm{flex:1}.ni .acc{font-size:12px;color:var(--muted)}
.tick{display:inline-flex;align-items:center;justify-content:center;width:16px;height:16px;border:1px solid var(--line);border-radius:50%;font-size:11px;flex:none}
.tick.y{background:var(--ok);border-color:var(--ok);color:#fff}
.prog{font-size:13px}
.progbar{height:6px;border-radius:3px;background:var(--line);margin-top:4px;overflow:hidden}
.progbar i{display:block;height:100%;background:var(--ok)}
.card.go{display:flex;justify-content:space-between;align-items:center;gap:12px}
.kgrid{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.kbox{padding:10px;border-radius:8px;background:var(--chip);display:flex;flex-direction:column;gap:4px;font-size:13px}
.h2.plain,h2.plain{margin:0 0 4px}
.prog2{height:4px;background:var(--line);border-radius:2px;margin:8px 0}
.prog2 i{display:block;height:100%;background:var(--brand-d)}
.hintbtn{margin-left:auto}
.teach{border:1px solid #cfe0f5;border-radius:12px;overflow:hidden;margin:12px 0;background:var(--card,#fff)}
.tc-hd{display:flex;align-items:center;gap:8px;padding:10px 14px;border-bottom:1px solid var(--line)}
.tc-tag{font-size:12px;font-weight:700;color:#fff;background:var(--brand-d);border-radius:5px;padding:2px 8px}
.tc-body{padding:6px 14px 12px}
.tc-b{margin-top:10px;padding:8px 12px;border-left:4px solid var(--line);border-radius:4px;background:var(--chip)}
.tc-b p,.tc-b ul,.tc-b ol{margin:4px 0}
.tc-k{font-size:12px;font-weight:700;color:var(--muted)}
.tc-b.blue{border-color:#2b6cb0}.tc-b.amber{border-color:#c2761a}.tc-b.green{border-color:#1f8a52}
.tc-b.remember{border-color:#ea580c;background:#fff7ed}.tc-b.remember .big{font-weight:700;color:#9a3412}
.tc-b.purple{border-color:#6b46c1}.tc-b.red{border-color:#c0392b}
.tc-b .ex{font-weight:600}
@media(max-width:899px){
  .side{position:fixed;left:0;top:0;z-index:20;transform:translateX(-100%);transition:transform .2s;width:84vw;max-width:320px}
  .side.open{transform:none}
  .mask.on{display:block;position:fixed;inset:0;background:rgba(0,0,0,.4);z-index:15}
  .burger{display:inline-block}
  .who em{display:none}
  .kgrid{grid-template-columns:1fr}
  .card.go{flex-direction:column;align-items:flex-start}
}

/* ===== 交互图形 / 符号速查 ===== */
.viz{border:1px solid var(--line);border-radius:12px;padding:10px 14px 12px;margin:12px 0;background:var(--card,#fff)}
.viz-hd{display:flex;align-items:center;gap:8px;margin-bottom:6px}
.viz-tag{background:#1f8a52}
.viz-svg{width:100%;max-width:520px;display:block;margin:0 auto;background:#fafcff;border-radius:8px}
.vg{stroke:#e5eaf2;stroke-width:1}.vax{stroke:#64748b;stroke-width:1.4}
.vt{font-size:10px;fill:#64748b}.vt.big{font-size:16px;font-weight:700;fill:#1e3a8a}
.vc1{stroke:#2a5298;stroke-width:2.6;fill:none}.vc2{stroke:#ea580c;stroke-width:2.6;fill:none}.vc3{stroke:#dc2626;stroke-width:3;fill:none}
rect.vc1{fill:#bfdbfe}
.vdash{stroke:#94a3b8;stroke-width:1.5;stroke-dasharray:5 4;fill:none}
.vsel{stroke:#16a34a;stroke-width:6;stroke-linecap:round}
.vdot{fill:#fff;stroke:#ea580c;stroke-width:2.5}
.vfill{fill:rgba(42,82,152,.25)}.vnone{fill:none}.vwhite{fill:#fafcff}.vring{fill:none;stroke:#1e3a8a;stroke-width:2}
.vctl{display:flex;flex-wrap:wrap;gap:8px 16px;margin:8px 0;align-items:center}
.vs{display:flex;align-items:center;gap:6px;font-size:13px}.vs input{width:130px}.vs b{min-width:2.4em}
.readout{padding:8px 10px;border-radius:8px;background:var(--chip);font-size:14px}
.viz-hint{margin:6px 0 0}
.symgrid{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.sym{display:flex;gap:10px;padding:8px 10px;border-radius:8px;background:var(--chip);font-size:14px}
.sym .sg{min-width:5.2em;font-size:17px;color:var(--brand-d);word-break:keep-all}
@media(max-width:700px){.symgrid{grid-template-columns:1fr}.vs input{width:100px}}
.vbar{fill:#93c5fd;cursor:pointer}.vbar.on{fill:#ea580c}
.vorg{stroke:#475569;stroke-width:1.5;cursor:pointer}.vorg.on{stroke:#dc2626;stroke-width:3.5}
.vwall{stroke:#16a34a;stroke-width:6}
.ctab{display:grid;gap:4px;margin:6px 0}.crow{display:flex;justify-content:space-between;padding:6px 10px;background:var(--chip);border-radius:6px;font-size:14px}

/* 教材单元 */
.tree details.unit{margin-left:6px;border-left:2px solid var(--line);padding-left:6px}
.tree details.unit>summary{font-weight:500;font-size:13px;color:var(--muted)}
.tree details.unit>summary span:first-child{flex:1;padding-right:6px}
.unitbox{margin-bottom:12px}.unit-t{font-weight:700;font-size:14px;color:var(--brand-d);padding:4px 0;border-bottom:1px solid var(--line);margin-bottom:4px}
.qn{font-weight:700;color:var(--brand-d)}