:root{
  --bg:#f5f7fb;--card:#fff;--ink:#1d2433;--muted:#667085;--line:#e4e8f0;
  --brand:#4f46e5;--brand-ink:#fff;--good:#16a34a;--warn:#d97706;--bad:#dc2626;--info:#2563eb;
  --unassessed:#cbd5e1;--weak:#ef4444;--learning:#f59e0b;--mastered:#22c55e;--radius:14px;
}
@media (prefers-color-scheme:dark){
  :root{--bg:#0f1420;--card:#171e2e;--ink:#e8ecf5;--muted:#9aa5bb;--line:#26304a;--brand:#818cf8;--brand-ink:#0f1420;--unassessed:#3a4560}
}
*{box-sizing:border-box}
html,body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.5 system-ui,-apple-system,"Segoe UI",Roboto,"Noto Sans SC",sans-serif}
button,input,select{font:inherit;color:inherit}
h1,h2,h3{line-height:1.2;margin:0 0 .5rem}
h1{font-size:1.6rem}h2{font-size:1.25rem}h3{font-size:1.05rem}
.wrap{max-width:1000px;margin:0 auto;padding:16px}
header.top{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 16px;background:var(--card);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:5}
header.top .brand{font-weight:700;font-size:1.1rem}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px;margin-bottom:16px}
.row{display:flex;gap:12px;flex-wrap:wrap;align-items:center}
.grow{flex:1 1 auto}
.grid{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(220px,1fr))}
.muted{color:var(--muted);font-size:.9rem}
.btn{background:var(--brand);color:var(--brand-ink);border:0;border-radius:10px;padding:10px 16px;cursor:pointer;font-weight:600}
.btn:hover{filter:brightness(1.08)}.btn:disabled{opacity:.5;cursor:default}
.btn.ghost{background:transparent;color:var(--ink);border:1px solid var(--line)}
.btn.danger{background:var(--bad);color:#fff}
.btn.sm{padding:5px 10px;font-size:.85rem;border-radius:8px}
input,select{width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:10px;background:var(--card)}
label{display:block;font-size:.85rem;color:var(--muted);margin:10px 0 4px}
.tabs{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:14px}
.tab{padding:8px 14px;border-radius:999px;border:1px solid var(--line);background:var(--card);cursor:pointer}
.tab.on{background:var(--brand);color:var(--brand-ink);border-color:var(--brand)}
.bar{height:12px;border-radius:99px;background:var(--unassessed);overflow:hidden}
.bar>i{display:block;height:100%;background:var(--brand)}
.bar.m>i{background:var(--mastered)}
.pill{display:inline-block;padding:2px 9px;border-radius:99px;font-size:.78rem;font-weight:600;color:#fff}
.pill.unassessed{background:#94a3b8}.pill.weak{background:var(--weak)}.pill.learning{background:var(--learning)}.pill.mastered{background:var(--mastered)}
.pill.focus{background:var(--brand);color:var(--brand-ink)}.pill.due{background:var(--info)}
.skill{display:grid;grid-template-columns:minmax(0,2fr) minmax(90px,1fr) auto;gap:10px;align-items:center;padding:8px 0;border-top:1px solid var(--line)}
.skill:first-child{border-top:0}
.skill .nm{font-weight:600}
.err{color:var(--bad);margin:8px 0}.ok{color:var(--good)}
table{width:100%;border-collapse:collapse;font-size:.9rem}
th,td{text-align:left;padding:6px 8px;border-bottom:1px solid var(--line);vertical-align:top}
.scroll{overflow-x:auto}
.mid{max-width:420px;margin:8vh auto}
.chart{width:100%;height:160px}
/* child area */
.kid{font-size:1.15rem}
.kid .subject{display:flex;flex-direction:column;gap:6px;padding:20px;border-radius:20px;border:3px solid var(--line);background:var(--card);cursor:pointer;text-align:left}
.kid .subject:hover{border-color:var(--brand);transform:translateY(-2px)}
.kid .subject .em{font-size:2.2rem}
.q-card{max-width:720px;margin:0 auto}
.q-text{font-size:1.5rem;font-weight:600;margin:12px 0 20px;white-space:pre-wrap}
.choices{display:grid;gap:10px}
.choice{padding:14px 16px;border-radius:14px;border:3px solid var(--line);background:var(--card);cursor:pointer;font-size:1.2rem;text-align:left}
.choice:hover{border-color:var(--brand)}
.choice.sel{border-color:var(--brand)}
.choice.right{border-color:var(--good);background:rgba(34,197,94,.15)}
.choice.wrong{border-color:var(--bad);background:rgba(239,68,68,.12)}
.big-input{font-size:1.5rem;padding:14px;text-align:center}
.fb{padding:14px;border-radius:14px;margin-top:14px;font-size:1.1rem}
.fb.good{background:rgba(34,197,94,.15)}.fb.bad{background:rgba(239,68,68,.12)}
.timer{font-variant-numeric:tabular-nums}
@media (max-width:560px){.skill{grid-template-columns:1fr auto}.skill .bar{grid-column:1/-1;order:3}.q-text{font-size:1.25rem}}

.stepper{display:flex;gap:6px;flex-wrap:wrap;margin:0 auto 14px;max-width:720px}
.stp{padding:4px 12px;border-radius:99px;background:var(--card);border:1px solid var(--line);font-size:.85rem;color:var(--muted)}
.stp.on{background:var(--brand);color:var(--brand-ink);border-color:var(--brand);font-weight:700}
.stp.done{color:var(--good)}
details>summary{cursor:pointer}

.scroll.tall{max-height:520px;overflow:auto}
.scroll.tall thead th{position:sticky;top:0;background:var(--card);z-index:1}

.gfx{margin:10px 0;border:2px solid var(--line);border-radius:12px;padding:6px 12px;background:var(--card);font-size:1rem;font-weight:500}
.gfx .gr{display:flex;align-items:center;gap:12px;padding:6px 0;border-bottom:1px dashed var(--line)}
.gfx .gr:last-child{border-bottom:0}
.gfx .gl{width:120px;flex:none;font-weight:700}
.gfx .gi{font-size:1.6rem;line-height:1.3;letter-spacing:2px;flex-wrap:wrap}
.gfx .gb{flex:1;height:22px;background:var(--bg);border-radius:6px;overflow:hidden}
.gfx .gb>i{display:block;height:100%;background:var(--brand);border-radius:6px}
.gfx .gv{min-width:56px;text-align:right;font-variant-numeric:tabular-nums}
.gtab{margin:8px 0;font-size:1rem}.gtab th{background:var(--bg)}

.ideas{padding-left:1.4rem;font-size:1.15rem}.ideas li{margin:8px 0}
.pop{animation:pop .35s ease}
@keyframes pop{0%{transform:scale(.92);opacity:.2}60%{transform:scale(1.04);opacity:1}100%{transform:scale(1)}}
@media (prefers-reduced-motion:reduce){.pop{animation:none}}

/* lesson visuals */
.pv{font-weight:700;padding:0 4px;border-radius:6px}
.pv-o{color:#c2410c;background:rgba(234,88,12,.12)}.pv-t{color:#15803d;background:rgba(22,163,74,.14)}.pv-h{color:#1d4ed8;background:rgba(37,99,235,.12)}.pv-th{color:#7e22ce;background:rgba(147,51,234,.12)}.pv-tth{color:#be123c;background:rgba(225,29,72,.12)}
th.pv-bg.pv-o{background:rgba(234,88,12,.18)}th.pv-bg.pv-t{background:rgba(22,163,74,.2)}th.pv-bg.pv-h{background:rgba(37,99,235,.18)}th.pv-bg.pv-th{background:rgba(147,51,234,.18)}th.pv-bg.pv-tth{background:rgba(225,29,72,.18)}
.vis{display:block;width:fit-content;max-width:100%;margin:8px 0}
.pvt,.colsum{border-collapse:separate;border-spacing:6px 2px;text-align:center;font-size:1.05rem}
.pvt th,.colsum th{font-size:.75rem;padding:2px 8px;border-radius:8px;border:0}
.pvt .dig td,.colsum td.d{font-size:1.6rem;font-weight:700;font-variant-numeric:tabular-nums;min-width:38px}
.pvt .blk td{font-size:.9rem;line-height:1.1;word-break:break-all;max-width:90px}.pvt .val td{color:var(--muted);font-size:.85rem}
.colsum tr.ln td.d{border-bottom:3px solid var(--ink)}.colsum td.sg{font-size:1.5rem;font-weight:700;text-align:right}
.colsum tr.rs td.d{color:var(--brand)}.colsum tr.mk td{height:20px;font-size:.85rem;font-weight:700}
.colsum td.mark.carry{color:#fff;background:#16a34a;border-radius:10px}.colsum td.mark.borrow{color:#fff;background:#dc2626;border-radius:10px}
.fbar{display:flex;align-items:center;gap:10px;margin:6px 0}.fb-row{display:flex;gap:3px}.fb-row i{display:block;width:34px;height:26px;border:2px solid var(--brand);border-radius:6px;background:transparent}.fb-row i.on{background:var(--brand)}
.arr{font-size:1.1rem;line-height:1.5}
ol.ideas{list-style:none;padding:0;counter-reset:idea}
ol.ideas>li{counter-increment:idea;position:relative;padding:6px 0 6px 46px;margin:10px 0}
ol.ideas>li::before{content:counter(idea);position:absolute;left:0;top:6px;width:32px;height:32px;border-radius:50%;background:var(--brand);color:var(--brand-ink);display:flex;align-items:center;justify-content:center;font-weight:700}

/* picture library */
figure.vfig{margin:10px 0;text-align:center}
figure.vfig figcaption{margin-top:4px}
.vrow{display:flex;flex-wrap:wrap;gap:14px;justify-content:center;align-items:flex-end}
.vcol{display:flex;flex-direction:column;align-items:center;gap:4px}
.vfrac{font-weight:700;font-size:1.1rem}
.vclock{display:flex;flex-wrap:wrap;gap:16px;justify-content:center;align-items:center}
.vdigital{font:700 2.2rem/1 ui-monospace,Menlo,Consolas,monospace;padding:12px 18px;border-radius:12px;background:#0f172a;color:#4ade80;letter-spacing:2px}
.vmoney{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;align-items:center}
.vmoney .coin{width:46px;height:46px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.85rem;color:#1f2937;border:3px solid rgba(0,0,0,.25)}
.vmoney .note{width:84px;height:44px;border-radius:6px;display:flex;align-items:center;justify-content:center;font-weight:800;color:#fff;border:2px solid rgba(0,0,0,.25)}
.vflow{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;align-items:center}
.vbox{padding:8px 14px;border-radius:12px;border:3px solid var(--brand);background:var(--card);font-weight:600}
.varrow{font-size:1.4rem;color:var(--brand)}
.vcard{display:flex;flex-direction:column;align-items:center;min-width:92px;padding:10px 12px;border-radius:14px;border:2px solid var(--line);background:var(--card)}
.vemoji{font-size:2.6rem;line-height:1.1}.vlabel{font-weight:700;font-size:1.1rem}
.vsent{display:flex;flex-direction:column;gap:8px;align-items:center}
.vsline{display:flex;flex-wrap:wrap;gap:6px;justify-content:center}
.vword{padding:2px 10px;border-radius:8px;border:2px solid;font-weight:700;font-size:1.15rem}
.vlegend{display:flex;flex-wrap:wrap;gap:12px;justify-content:center;font-size:.85rem;font-weight:600}
.vchar{display:inline-flex;flex-direction:column;align-items:center;padding:10px 26px;border-radius:16px;border:3px solid var(--brand);background:var(--card)}
.vbig{font-size:4.5rem;line-height:1.1}.vpin{font-size:1.3rem;color:var(--brand);font-weight:700}

.gfx-in{min-width:260px;text-align:left}.gfx-in .gr{display:flex;align-items:center;gap:12px;padding:6px 0;border-bottom:1px dashed var(--line)}.gfx-in .gr:last-of-type{border-bottom:0}
.gfx-in .gl{width:110px;flex:none;font-weight:700}.gfx-in .gi{font-size:1.5rem;line-height:1.3;letter-spacing:2px}
.gfx-in .gb{flex:1;height:22px;background:var(--bg);border-radius:6px;overflow:hidden;min-width:120px}.gfx-in .gb>i{display:block;height:100%;background:var(--brand);border-radius:6px}.gfx-in .gv{min-width:56px;text-align:right}
.vlegcol{flex-direction:column;align-items:flex-start;gap:4px}

.vlisten{display:flex;flex-direction:column;align-items:center;gap:8px;padding:6px}
.vlisten .btn{font-size:1.2rem;padding:12px 26px}
.vtranscript{white-space:pre-wrap;text-align:left;padding:8px 12px;border-radius:10px;background:var(--bg);font-size:.95rem}

.vpin{font-size:1.2rem;color:var(--brand);font-weight:700;letter-spacing:1px}