:root{font-family:Inter,"Noto Sans TC","PingFang TC","Microsoft JhengHei",system-ui,sans-serif;color:#111827;background:#f8fafc;--blue:#2563eb;--green:#10b981;--orange:#f59e0b;--red:#ef4444;--purple:#7c3aed;--border:#e5e7eb;--muted:#64748b;--surface:#fff}
*{box-sizing:border-box}body{margin:0;background:#f8fafc;color:#111827}.app-shell{max-width:920px;margin:auto;padding:18px 18px 54px}.topbar{display:flex;justify-content:space-between;align-items:center;gap:16px;margin-bottom:18px}.topbar h1{font-size:clamp(26px,4vw,38px);margin:0;letter-spacing:-.03em}.topbar p{margin:6px 0 0;color:var(--muted)}button,input{font:inherit}.controls,.study-card,.browser-panel{background:var(--surface);border:1px solid var(--border);border-radius:20px;box-shadow:0 8px 28px rgba(15,23,42,.06)}.controls{padding:16px}.control-row{display:flex;gap:8px;flex-wrap:wrap}.control-row+.control-row{margin-top:12px}.level-btn,.secondary,.ghost,.answer{border:0;border-radius:12px;padding:10px 14px;cursor:pointer;font-weight:700}.level-btn{background:#eef2ff;color:#334155}.level-btn.active{background:var(--blue);color:white}.secondary{background:#eff6ff;color:#1d4ed8}.ghost{background:#f1f5f9;color:#475569}.hidden{display:none!important}#searchInput{flex:1;min-width:220px;border:1px solid var(--border);border-radius:12px;padding:11px 13px;outline:none}#searchInput:focus{border-color:#93c5fd;box-shadow:0 0 0 3px #dbeafe}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:14px 0}.stats>div{background:white;border:1px solid var(--border);border-radius:16px;padding:14px;text-align:center}.stats strong{display:block;font-size:24px}.stats span{display:block;color:var(--muted);font-size:13px;margin-top:3px}.study-card{padding:18px}.card-meta{display:flex;justify-content:space-between;color:var(--muted);font-size:13px}.card-meta span:first-child{color:#1d4ed8;background:#eff6ff;border-radius:999px;padding:6px 9px;font-weight:800}.word-area{width:100%;border:0;background:transparent;padding:38px 12px 26px;cursor:pointer}.word{font-size:clamp(44px,9vw,76px);font-weight:800;letter-spacing:-.04em;line-height:1.05}.meaning{margin:20px auto 0;max-width:700px;font-size:clamp(18px,3.5vw,28px);line-height:1.55;color:#334155}.meaning.concealed{visibility:hidden}.hint{margin-top:16px;color:#94a3b8;font-size:13px}.nav-row,.answer-row{display:grid;gap:10px}.nav-row{grid-template-columns:1fr 1fr 1fr;margin-top:6px}.answer-row{grid-template-columns:repeat(4,1fr);margin-top:12px}.answer.known{background:#ecfdf5;color:#047857}.answer.unsure{background:#fffbeb;color:#b45309}.answer.unknown{background:#fef2f2;color:#b91c1c}.answer.skip{background:#f5f3ff;color:#6d28d9}.browser-panel{padding:16px;margin-top:14px}.panel-head{display:flex;justify-content:space-between;align-items:center}.panel-head h2{font-size:18px;margin:0}.word-list{margin-top:12px;max-height:500px;overflow:auto;border-top:1px solid var(--border)}.word-row{display:grid;grid-template-columns:62px 1.2fr 2fr;gap:10px;padding:11px 4px;border-bottom:1px solid #f1f5f9;align-items:start}.word-row button{border:0;background:transparent;text-align:left;padding:0;cursor:pointer;color:#111827;font-weight:700}.lv{font-weight:800;color:#2563eb}.zh{color:#475569;line-height:1.45;font-size:14px}@media(max-width:620px){.app-shell{padding:14px 12px 40px}.topbar{align-items:flex-start}.stats{grid-template-columns:repeat(2,1fr)}.nav-row{grid-template-columns:1fr 1fr 1fr}.answer-row{grid-template-columns:repeat(2,1fr)}.word-row{grid-template-columns:48px 1fr;}.word-row .zh{grid-column:2}.word-area{padding:32px 6px 22px}}
@media(prefers-color-scheme:dark){:root{color:#e5e7eb;background:#0f172a;--surface:#111827;--border:#263244;--muted:#94a3b8}body{background:#0f172a}.controls,.study-card,.browser-panel,.stats>div{background:#111827}.word,.word-row button{color:#f8fafc}.meaning,.zh{color:#cbd5e1}.level-btn{background:#1e293b;color:#cbd5e1}.secondary{background:#172554;color:#bfdbfe}.ghost{background:#1e293b;color:#cbd5e1}#searchInput{background:#0f172a;color:#f8fafc}.answer.known{background:#052e2b;color:#6ee7b7}.answer.unsure{background:#451a03;color:#fcd34d}.answer.unknown{background:#450a0a;color:#fca5a5}.answer.skip{background:#2e1065;color:#c4b5fd}}