.math-btn{display:inline-flex;align-items:center;justify-content:center;width:100%;min-height:2.75rem;padding:.55rem .5rem;border-radius:.75rem;border:2px solid var(--btn-color, #2563EB);background-color:#fff;color:var(--btn-color, #2563EB);font-size:.875rem;font-weight:700;line-height:1.2;transition:background-color .15s ease,color .15s ease,box-shadow .15s ease,transform .12s ease;cursor:pointer}.math-btn--mode,.math-btn--level{--btn-color: #2563EB}.math-btn:hover{transform:translateY(-1px);background-color:color-mix(in srgb,var(--btn-color) 8%,#fff)}.math-btn.is-active{background-color:var(--btn-color);color:var(--btn-fg, #fff);box-shadow:0 3px 10px color-mix(in srgb,var(--btn-color) 35%,transparent)}.math-btn.is-active:hover{background-color:var(--btn-color);color:var(--btn-fg, #fff)}.math-start-btn{display:inline-flex;align-items:center;justify-content:center;gap:.35rem;padding:.85rem 2.25rem;border-radius:9999px;border:none;background:linear-gradient(135deg,#3b82f6,#8b5cf6);color:#fff;font-size:.95rem;font-weight:700;box-shadow:0 6px 16px #3b82f659;cursor:pointer;transition:transform .15s ease,box-shadow .15s ease}.math-start-btn:hover{transform:translateY(-2px) scale(1.03);box-shadow:0 8px 20px #3b82f673}.math-start-btn--sm{padding:.6rem 1.5rem;font-size:.875rem}.math-problem-card{min-height:8.5rem;background:linear-gradient(180deg,#eff6ff,#fff 55%)}.math-problem-text{font-size:clamp(2rem,8vw,3rem);letter-spacing:.04em}.math-choices{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.65rem;max-width:28rem;margin:0 auto}.math-choice{display:flex;align-items:center;gap:.65rem;min-height:3.4rem;padding:.7rem .9rem;border-radius:.85rem;border:2px solid var(--color-border);background:#fff;color:var(--color-text);font-size:1.35rem;font-weight:800;cursor:pointer;transition:background-color .12s ease,border-color .12s ease,transform .12s ease,opacity .12s ease}.math-choice:hover:not(:disabled){border-color:var(--color-accent);background:#eff6ff;transform:translateY(-1px)}.math-choice:disabled{cursor:default;opacity:.72}.math-choice__key{display:inline-flex;align-items:center;justify-content:center;width:1.5rem;height:1.5rem;border-radius:.4rem;background:var(--color-accent-light);color:var(--color-accent-dark);font-size:.75rem;font-weight:800;flex-shrink:0}.math-choice__value{min-width:0;text-align:left;font-variant-numeric:tabular-nums}.math-choice.is-correct{border-color:#16a34a;background:#f0fdf4;color:#166534;opacity:1}.math-choice.is-wrong{border-color:#dc2626;background:#fef2f2;color:#991b1b;opacity:1}.math-choice.is-dim{opacity:.45}.math-countdown{position:absolute;inset:0;z-index:10;display:flex;align-items:center;justify-content:center;background:#0f172a38;border-radius:inherit}.math-countdown.hidden{display:none}.math-countdown__num{font-size:clamp(3.5rem,16vw,5.5rem);font-weight:800;color:#fff;text-shadow:0 6px 20px rgba(37,99,235,.55)}.math-countdown-pop{animation:mathCountdownPop .55s ease-out}@keyframes mathCountdownPop{0%{transform:scale(1.4);opacity:.2}to{transform:scale(1);opacity:1}}.math-shake{animation:mathShake .35s ease}@keyframes mathShake{0%,to{transform:translate(0)}25%{transform:translate(-6px)}75%{transform:translate(6px)}}.result-card{border-radius:var(--radius-lg);border:1px solid var(--color-border);background:linear-gradient(180deg,#fdf4ff,#eff6ff)}.cert-panel{margin-top:.25rem;padding:.9rem 1rem;border-radius:var(--radius-md);border:1px solid color-mix(in srgb,#2563EB 28%,var(--color-border));background:color-mix(in srgb,#EFF6FF 80%,#fff)}.math-cert-btn{display:inline-flex;align-items:center;justify-content:center;gap:.4rem;padding:.7rem 1rem;border-radius:9999px;border:none;font-size:.875rem;font-weight:700;color:#fff;background:linear-gradient(135deg,#2563eb,#059669);box-shadow:0 4px 12px #2563eb47;cursor:pointer}.math-cert-btn--secondary{color:#1e3a5f;background:linear-gradient(135deg,#e0f2fe,#d1fae5);box-shadow:0 2px 8px #2563eb1f;border:1px solid color-mix(in srgb,#2563EB 25%,transparent)}.math-cert-btn:disabled{opacity:.65;cursor:not-allowed}.sound-panel{padding:.85rem 1rem;border:1px solid var(--color-border);border-radius:var(--radius-md);background:color-mix(in srgb,var(--color-bg, #f8fafc) 70%,#fff)}.sound-row{display:grid;grid-template-columns:5.5rem 1fr;gap:.65rem .85rem;align-items:center}@media(max-width:520px){.sound-row{grid-template-columns:1fr;gap:.4rem}}.sound-row-label{margin:0;font-size:.8rem;font-weight:700;color:var(--color-text);white-space:nowrap}.sound-row-controls{display:flex;flex-wrap:wrap;align-items:center;gap:.5rem .65rem;min-width:0}.sound-toggle{display:inline-flex;align-items:center;justify-content:center;gap:.3rem;min-width:4.5rem;padding:.4rem .7rem;border-radius:9999px;border:2px solid #94a3b8;background:#f1f5f9;color:#64748b;font-size:.75rem;font-weight:700;transition:background-color .15s ease,color .15s ease,border-color .15s ease}.sound-toggle.is-on{border-color:#2563eb;background:#2563eb;color:#fff}.sound-field{display:inline-flex;align-items:center;gap:.4rem;min-width:0;padding:.3rem .55rem;border:1px solid var(--color-border);border-radius:.55rem;background:#fff}.sound-field--volume{flex:1 1 12rem;min-width:10rem}.sound-field--narrow{flex:0 0 auto;width:7.5rem}.sound-field-label{flex-shrink:0;font-size:.7rem;font-weight:700;color:var(--color-text-muted);letter-spacing:.02em}.sound-range{flex:1 1 auto;width:100%;min-width:0;accent-color:var(--color-accent)}.sound-select{flex:1 1 auto;min-width:0;width:100%;border:none;background:transparent;font-size:.75rem;font-weight:600;color:var(--color-text);outline:none;cursor:pointer}