:root{--bg: #f4f4f5;--card: #ffffff;--text: #18181b;--muted: #5c5c66;--border: #d4d4d8;--border-strong: #a1a1aa;--dark: #27272a;--good: #3f6212;--bad: #991b1b;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--text);background:var(--bg)}*{box-sizing:border-box;border-radius:0!important}body{margin:0;background:var(--bg)}main{max-width:640px;margin:0 auto;padding:40px 16px 64px}header{display:flex;align-items:center;justify-content:space-between;margin-bottom:24px;padding-bottom:12px;border-bottom:1px solid var(--border)}h1{font-size:1.25rem;margin:0;letter-spacing:.02em;text-transform:uppercase}h2{font-size:1.1rem;margin:0 0 16px}.card{background:var(--card);border:1px solid var(--border);padding:24px}button{font:inherit;cursor:pointer}.btn{padding:10px 18px;border:1px solid var(--dark);background:var(--dark);color:#fff}.btn:hover{background:#000}.btn.secondary{background:var(--card);color:var(--text);border-color:var(--border-strong)}.btn.secondary:hover{background:var(--bg)}.link{background:none;border:none;color:var(--muted);padding:0;font-size:.9rem}.link:hover{color:var(--text);text-decoration:underline}.picker{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.mode{display:flex;flex-direction:column;align-items:center;gap:14px;padding:32px 16px;background:var(--card);border:1px solid var(--border);color:var(--text)}.mode:hover{border-color:var(--dark)}.mode svg{width:72px;height:72px}.mode .label{font-weight:600}.mode .sub{color:var(--muted);font-size:.85rem}.field{display:flex;flex-direction:column;gap:6px;margin-bottom:18px}.field label{font-size:.85rem;color:var(--muted);text-transform:uppercase;letter-spacing:.04em}.row{display:grid;grid-template-columns:1fr 1fr;gap:16px}input[type=number],.answer input{width:100%;padding:10px 12px;font-size:1rem;border:1px solid var(--border-strong);background:var(--card);color:var(--text)}input:focus{outline:2px solid var(--dark);outline-offset:-2px}.presets{display:flex;gap:8px;flex-wrap:wrap}.presets button{padding:6px 14px;border:1px solid var(--border-strong);background:var(--card);color:var(--text)}.presets button.active{background:var(--dark);color:#fff;border-color:var(--dark)}.error{color:var(--bad);font-size:.9rem;margin:-6px 0 14px}.actions{display:flex;gap:8px;justify-content:flex-end;margin-top:8px}.progress-text{display:flex;justify-content:space-between;color:var(--muted);font-size:.85rem;margin-bottom:8px}.progress{height:4px;background:var(--border);margin-bottom:24px}.progress>div{height:100%;background:var(--dark);transition:width .2s}.big{font-size:2.6rem;font-weight:700;text-align:center;margin:16px 0 28px;font-variant-numeric:tabular-nums}.question{font-size:1.15rem;line-height:1.5;margin:8px 0 24px}.answer{display:flex;gap:8px}.answer input{flex:1;min-width:0;font-size:1.1rem}.hint{color:var(--muted);font-size:.85rem;margin:12px 0 0}code{background:var(--bg);border:1px solid var(--border);padding:0 4px}.summary{display:grid;grid-template-columns:repeat(3,1fr);border:1px solid var(--border);margin-bottom:20px}.summary>div{padding:16px;text-align:center}.summary>div+div{border-left:1px solid var(--border)}.summary .num{font-size:1.8rem;font-weight:700;font-variant-numeric:tabular-nums}.summary .cap{color:var(--muted);font-size:.8rem;text-transform:uppercase;letter-spacing:.04em}.review{list-style:none;padding:0;margin:0 0 20px;border:1px solid var(--border)}.review li{padding:12px 14px;border-left:4px solid var(--good)}.review li+li{border-top:1px solid var(--border)}.review li.wrong{border-left-color:var(--bad);background:#fafafa}.review .q{margin-bottom:4px}.review .detail{font-size:.9rem;color:var(--muted);word-break:break-word}.review .detail b{color:var(--text)}.review .mark{font-weight:700;margin-right:6px}.review li:not(.wrong) .mark{color:var(--good)}.review li.wrong .mark{color:var(--bad)}.review .why{font-size:.85rem;margin-top:4px;color:var(--text)}@media (max-width: 480px){.picker,.row{grid-template-columns:1fr}.summary .num{font-size:1.4rem}}header nav{display:flex;gap:16px}h3{font-size:.85rem;color:var(--muted);text-transform:uppercase;letter-spacing:.04em;margin:24px 0 10px;font-weight:600}.check{display:flex;align-items:center;gap:10px;margin:4px 0 20px;cursor:pointer}.check input{width:18px;height:18px;accent-color:var(--dark);margin:0}.field-hint{margin:-8px 0 18px}.tabs-row{margin-bottom:20px}.feedback{margin-top:16px;padding:12px 14px;border:1px solid var(--border);border-left:4px solid var(--good);background:#fafafa;word-break:break-word}.feedback.correct b:first-child{color:var(--good)}.feedback.wrong{border-left-color:var(--bad)}.feedback.wrong b:first-child{color:var(--bad)}.feedback .time{color:var(--muted)}.quit-box{border:1px solid var(--border);background:#fafafa;padding:16px}.quit-box p{margin:0 0 12px}.quit-box .actions{flex-wrap:wrap}.btn:disabled{opacity:.4;cursor:not-allowed}.minor-stats{display:flex;flex-wrap:wrap;gap:8px 20px;color:var(--muted);font-size:.9rem;margin-top:-8px}.minor-stats b{color:var(--text)}.qtime{float:right;color:var(--muted);font-size:.85rem;font-variant-numeric:tabular-nums}.chart{position:relative;width:100%;border:1px solid var(--border);background:var(--card)}.chart svg{display:block}.chart .grid{stroke:#e4e4e7;stroke-width:1}.chart .axis{fill:var(--muted);font-size:11px;font-variant-numeric:tabular-nums}.chart .line{fill:none;stroke:var(--dark);stroke-width:2;stroke-linejoin:round}.chart .dot{fill:var(--dark);stroke:#fff;stroke-width:2}.chart .dot.current{fill:#fff;stroke:var(--dark);stroke-width:2.5}.chart .crosshair{stroke:var(--border-strong);stroke-width:1;stroke-dasharray:3 3}.tooltip{position:absolute;background:var(--card);border:1px solid var(--dark);padding:8px 10px;font-size:.8rem;line-height:1.45;white-space:nowrap;pointer-events:none;box-shadow:2px 2px #00000014}.tt-title{color:var(--muted)}.table-view{margin-top:12px;font-size:.9rem}.table-view summary{cursor:pointer;color:var(--muted)}.table-view table{width:100%;border-collapse:collapse;margin-top:8px;font-variant-numeric:tabular-nums}.table-view th,.table-view td{text-align:left;padding:6px 8px;border-bottom:1px solid var(--border)}.table-view th{color:var(--muted);font-weight:600;font-size:.8rem}.card>.actions:last-child{margin-top:20px}@media (max-width: 600px){.picker{grid-template-columns:1fr}.summary .cap{font-size:.7rem}}:focus-visible{outline:2px solid var(--dark);outline-offset:2px}.btn:focus-visible{outline-offset:2px}.mode:focus-visible{outline:2px solid var(--dark);outline-offset:-2px}footer{max-width:640px;margin:0 auto;padding:16px 16px 8px;border-top:1px solid var(--border);display:flex;flex-wrap:wrap;gap:8px 20px;font-size:.85rem}footer a{color:var(--muted)}footer a:hover{color:var(--text)}.legal{line-height:1.6}.legal h2{font-size:1.4rem;margin-bottom:4px}.legal h3{margin-top:28px}.legal .updated{color:var(--muted);font-size:.85rem;margin:0 0 20px}.legal p,.legal li{font-size:.95rem}.legal ul{padding-left:20px}.legal li+li{margin-top:6px}.legal a,.hint a{color:var(--text)}header{flex-wrap:wrap;gap:8px 16px}footer .gh{display:inline-flex;align-items:center;gap:6px}.badge-wrap{display:flex;justify-content:center;padding:8px 16px 40px}.logo{cursor:pointer;-webkit-user-select:none;user-select:none}.btn,.link,.presets button,.mode,input,footer a{transition:background-color .18s ease,border-color .18s ease,color .18s ease}.btn{will-change:transform}.mode .icon{display:grid;place-items:center}.presets button.op{position:relative;overflow:hidden;min-width:44px;font-size:1.05rem}.presets button.op.active{background:var(--card);color:#fff;border-color:var(--dark)}.op-fill{position:absolute;top:0;right:0;bottom:0;left:0;background:var(--dark);transform-origin:bottom}.op-label,.presets button.tab{position:relative}.presets button.tab.active{background:var(--card);color:#fff;border-color:var(--dark)}.tab-highlight{position:absolute;top:-1px;right:-1px;bottom:-1px;left:-1px;background:var(--dark)}.tab-label{position:relative}.qnum{display:inline-block;min-width:1ch;text-align:center;color:var(--text)}.prompt-stage{position:relative;overflow:hidden}.answer input.is-correct{border-color:var(--good)}.answer input.is-wrong{border-color:var(--bad)}.feedback{padding:0;margin-top:0;overflow:hidden}.feedback-inner{padding:12px 14px}.error{margin:0;overflow:hidden}.chart .area{fill:#27272a0f}.chart .pulse{fill:none;stroke:var(--dark);stroke-width:1.5}