:root{--primary: #6366f1;--bg: #f0f4ff;--card: #ffffff;--text: #1e293b;--accent: #fbbf24;--danger: #ef4444;--success: #22c55e}body{margin:0;font-family:Inter,system-ui,-apple-system,sans-serif;background-color:var(--bg);color:var(--text);display:flex;justify-content:center;align-items:center;min-height:100vh;overflow:hidden}.math-app{width:100%;max-width:420px;height:90vh;background:var(--card);border-radius:32px;box-shadow:0 20px 50px #0000001a;position:relative;display:flex;flex-direction:column;overflow:hidden}.cloud-sync-bar{position:absolute;top:12px;left:50%;transform:translate(-50%);background:#fffc;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);padding:4px 12px;border-radius:20px;font-size:10px;color:#94a3b8;display:flex;align-items:center;gap:6px;z-index:10;border:1px solid #e2e8f0}.syncing{animation:spin 2s linear infinite}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.screen{flex:1;display:flex;flex-direction:column;padding:30px;align-items:center;justify-content:center}.start-screen h1{font-size:32px;margin:20px 0 10px;background:linear-gradient(135deg,var(--primary),#a855f7);-webkit-background-clip:text;-webkit-text-fill-color:transparent}.start-screen p{color:#64748b;margin-bottom:30px}.high-score-badge{background:#fffbeb;color:#b45309;padding:10px 20px;border-radius:16px;display:flex;align-items:center;gap:8px;font-weight:700;margin-bottom:40px;border:1px solid #fef3c7}.game-header{width:100%;display:flex;justify-content:space-between;margin-bottom:40px}.stat-item{display:flex;align-items:center;gap:6px;font-weight:800;font-size:18px}.timer span.urgent{color:var(--danger);animation:pulse .5s infinite alternate}@keyframes pulse{0%{transform:scale(1)}to{transform:scale(1.1)}}.question-area{flex:1;display:flex;align-items:center;justify-content:center;width:100%}.equation{display:flex;align-items:center;gap:12px;font-size:36px;font-weight:900;color:var(--primary)}.answer-box{min-width:80px;height:60px;background:#f8fafc;border-bottom:4px solid var(--primary);display:flex;align-items:center;justify-content:center;color:var(--text);border-radius:8px}.keypad{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;width:100%;margin-top:20px}.key{height:60px;border:none;background:#f1f5f9;border-radius:16px;font-size:20px;font-weight:600;color:var(--text);cursor:pointer;transition:all .2s;display:flex;align-items:center;justify-content:center}.key:active{transform:scale(.95);background:#e2e8f0}.key.special{background:#e0e7ff;color:var(--primary)}.key:last-child{background:var(--primary);color:#fff}.mini-history{display:flex;gap:6px;margin-top:20px}.history-dot{width:20px;height:20px;border-radius:50%;display:flex;align-items:center;justify-content:center}.history-dot.correct{background:#dcfce7;color:var(--success)}.history-dot.wrong{background:#fee2e2;color:var(--danger)}.main-btn{background:var(--primary);color:#fff;border:none;padding:16px 40px;border-radius:20px;font-size:18px;font-weight:700;display:flex;align-items:center;gap:10px;cursor:pointer;box-shadow:0 10px 20px #6366f14d}.main-btn.secondary{background:#f1f5f9;color:var(--text);box-shadow:none;margin-top:20px}.final-stats{display:flex;gap:20px;margin:30px 0}.stat-card{background:#f8fafc;padding:20px;border-radius:20px;text-align:center;flex:1}.stat-card label{font-size:12px;color:#64748b}.stat-card .val{font-size:24px;font-weight:800;color:var(--primary)}.new-record{color:var(--accent);font-weight:800;margin-bottom:20px}.history-list{width:100%;max-height:200px;overflow-y:auto;margin-bottom:20px}.history-row{display:flex;justify-content:space-between;padding:8px 0;border-bottom:1px solid #f1f5f9;font-size:14px}.text-correct{color:var(--success);font-weight:700}.text-wrong{color:var(--danger);font-weight:700}