:root{color-scheme:dark;--bg: #0b0d10;--bg-elev: #15191f;--bg-elev-2: #1c2128;--border: #2a2f37;--text: #e8eaed;--text-dim: #9aa0a6;--accent: #4f8cff;--accent-text: #ffffff;--good: #2fbf71;--bad: #ef4444;--warn: #f59e0b;--radius: 12px;--tap: 44px;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,system-ui,sans-serif;font-size:16px;line-height:1.45}*{box-sizing:border-box}html,body,#root{margin:0;padding:0;min-height:100%;background:var(--bg);color:var(--text);-webkit-tap-highlight-color:transparent}body{padding:env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left)}a{color:var(--accent);text-decoration:none}button{font:inherit;color:inherit;background:transparent;border:1px solid var(--border);border-radius:var(--radius);padding:12px 16px;min-height:var(--tap);cursor:pointer;touch-action:manipulation}button:disabled{opacity:.5;cursor:not-allowed}button.primary{background:var(--accent);border-color:var(--accent);color:var(--accent-text);font-weight:600}button.danger{border-color:var(--bad);color:var(--bad)}button.ghost{border-color:transparent}button.full{width:100%}input[type=text],input[type=number],textarea,select{font:inherit;color:inherit;background:var(--bg-elev);border:1px solid var(--border);border-radius:var(--radius);padding:12px 14px;min-height:var(--tap);width:100%}textarea{min-height:96px;resize:vertical}.app{max-width:720px;margin:0 auto;padding:16px 16px 96px}.app-header{display:flex;align-items:center;justify-content:space-between;padding:8px 16px 16px;max-width:720px;margin:0 auto}.app-header h1{font-size:18px;margin:0}.app-header .back{font-size:14px;color:var(--text-dim)}.card{background:var(--bg-elev);border:1px solid var(--border);border-radius:var(--radius);padding:16px;margin-bottom:12px}.card h2{font-size:16px;margin:0 0 8px}.card .meta{color:var(--text-dim);font-size:13px}.stack{display:flex;flex-direction:column;gap:12px}.row{display:flex;gap:8px;flex-wrap:wrap}.row.between{justify-content:space-between;align-items:center}.muted{color:var(--text-dim)}.small{font-size:13px}.center{text-align:center}.issue{border-left:3px solid var(--border);padding:8px 12px;margin-bottom:8px;background:var(--bg-elev-2);border-radius:8px;font-size:14px}.issue.error{border-left-color:var(--bad)}.issue.warning{border-left-color:var(--warn)}.issue .path{color:var(--text-dim);font-size:12px;font-family:ui-monospace,Menlo,monospace}.answer-option{display:flex;align-items:flex-start;gap:12px;border:1px solid var(--border);border-radius:var(--radius);padding:12px 14px;background:var(--bg-elev);cursor:pointer;-webkit-user-select:none;user-select:none;text-align:left;width:100%;min-height:var(--tap)}.answer-option.selected{border-color:var(--accent);background:#4f8cff14}.answer-option.correct{border-color:var(--good);background:#2fbf7114}.answer-option.incorrect{border-color:var(--bad);background:#ef444414}.answer-option .marker{width:22px;height:22px;border-radius:6px;border:1px solid var(--border);flex-shrink:0;display:flex;align-items:center;justify-content:center;font-size:13px}.answer-option.selected .marker,.answer-option.correct .marker{border-color:currentColor}.feedback{border-radius:var(--radius);padding:14px;margin-top:12px;border:1px solid var(--border);background:var(--bg-elev-2)}.feedback.correct{border-color:var(--good)}.feedback.incorrect{border-color:var(--bad)}.feedback h3{margin:0 0 6px;font-size:15px}.case-card{background:var(--bg-elev-2);border:1px solid var(--border);border-radius:var(--radius);padding:14px;margin-bottom:12px;white-space:pre-wrap;max-height:40vh;overflow:auto}.progress{display:flex;gap:4px;margin-bottom:12px}.progress span{flex:1;height:4px;background:var(--border);border-radius:2px}.progress span.done{background:var(--accent)}.tag{display:inline-block;font-size:12px;color:var(--text-dim);border:1px solid var(--border);border-radius:999px;padding:2px 8px;margin-right:6px;margin-top:6px}.empty{text-align:center;padding:40px 16px;color:var(--text-dim)}