*{margin:0;padding:0;box-sizing:border-box;-webkit-tap-highlight-color:transparent}body{font-family:Comic Sans MS,Arial Rounded MT Bold,cursive,sans-serif;overflow:hidden;-webkit-user-select:none;user-select:none}.game-container{width:100vw;height:100vh;background:linear-gradient(180deg,#1a472a,#2d5a3f 30%,#87ceeb 70%,#fff);position:relative;overflow:hidden;touch-action:manipulation}.snowflakes{position:absolute;width:100%;height:100%;pointer-events:none;z-index:1}.snowflake{position:absolute;color:#fff;animation:fall linear infinite;opacity:.9}@keyframes fall{0%{transform:translateY(-10vh) rotate(0)}to{transform:translateY(110vh) rotate(360deg)}}.christmas-lights{position:absolute;top:60px;left:0;width:100%;z-index:2}.light{position:absolute;font-size:1rem;animation:twinkle .5s ease infinite alternate}@keyframes twinkle{0%{opacity:.5;transform:scale(.8)}to{opacity:1;transform:scale(1.2)}}.santa-sleigh{position:absolute;top:45%;left:-100px;z-index:3;animation:santaFly 25s linear infinite}.santa-ride{font-size:3rem;filter:drop-shadow(0 5px 10px rgba(0,0,0,.3))}@keyframes santaFly{0%{left:-100px;transform:translateY(0) rotate(0)}25%{transform:translateY(-30px) rotate(2deg)}50%{transform:translateY(0) rotate(0)}75%{transform:translateY(30px) rotate(-2deg)}to{left:110%;transform:translateY(0) rotate(0)}}.bottom-santa{position:absolute;bottom:100px;left:20px;font-size:4rem;z-index:5;animation:santaWave 2s ease-in-out infinite;filter:drop-shadow(0 5px 15px rgba(0,0,0,.3))}@keyframes santaWave{0%,to{transform:rotate(-5deg) translateY(0)}50%{transform:rotate(5deg) translateY(-10px)}}.game-title{position:absolute;top:15px;left:50%;transform:translate(-50%);z-index:10;width:100%;text-align:center}.game-title h1{font-size:1.3rem;color:#fff;text-shadow:2px 2px 4px rgba(0,0,0,.3),0 0 20px rgba(255,215,0,.5);background:linear-gradient(45deg,#ff6b6b,#ffd93d,#ff6b6b);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;animation:titleGlow 2s 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h2{font-size:1.8rem;color:#ffd93d;margin-bottom:10px;text-shadow:2px 2px 4px rgba(0,0,0,.3)}.intro-text{font-size:1.1rem;color:#fff;margin-bottom:20px}.mode-select{background:#ffffffe6;padding:15px;border-radius:20px;margin-bottom:15px;box-shadow:0 5px 20px #0003}.mode-select h3{text-align:center;color:#1a472a;margin-bottom:12px;font-size:1rem}.mode-buttons{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}.mode-btn{padding:12px 15px;font-size:1rem;border:3px solid #ddd;border-radius:12px;background:#fff;cursor:pointer;transition:all .2s;font-weight:700}.mode-btn.selected{border-color:#ff6b6b;background:linear-gradient(135deg,#fff5f5,#ffe0e0);transform:scale(1.02)}.mode-btn:active{transform:scale(.95)}.hint{color:#ffd93d;font-size:.85rem;margin-bottom:15px}.start-buttons{display:flex;gap:15px;margin-bottom:15px}.start-btn,.history-btn{padding:15px 30px;font-size:1.2rem;border:none;border-radius:25px;color:#fff;cursor:pointer;font-weight:700;transition:all .2s}.start-btn{background:linear-gradient(45deg,#ff6b6b,#ee5a5a);box-shadow:0 5px 20px #ff6b6b66}.start-btn:disabled{background:#ccc;cursor:not-allowed;box-shadow:none}.history-btn{background:linear-gradient(45deg,#1e90ff,#00bfff);box-shadow:0 5px 20px #1e90ff66}.start-buttons button:hover{transform:scale(1.05)}.best-records{display:flex;gap:20px;background:#ffffffe6;padding:10px 25px;border-radius:15px}.best-item{font-size:1rem;color:#1a472a;font-weight:700}.game-area{position:absolute;top:120px;left:0;width:100%;height:calc(100% - 120px);display:flex;flex-direction:column;align-items:center;padding:15px 15px 100px}.game-stats{display:flex;gap:15px;margin-bottom:15px}.stat{background:#ffffffe6;padding:8px 15px;border-radius:15px;font-size:1rem;font-weight:700;box-shadow:0 3px 10px #0000001a}.stat.score{color:#ffd93d}.stat.combo{color:#ff6b6b;opacity:.5}.stat.combo-active{opacity:1;animation:pulse .3s ease 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#ffd93d;margin-bottom:25px;text-align:center;min-height:160px}.question-number{font-size:.9rem;color:#888;margin-bottom:8px}.question-formula{font-size:3rem;font-weight:700;color:#1a472a;display:flex;align-items:center;justify-content:center;gap:10px}.operator,.equals{color:#ff6b6b}.answer-display{display:inline-flex;align-items:center;justify-content:center;min-width:60px;padding:5px 15px;font-size:2.5rem;font-weight:700;color:#ffd93d;background:#ffffffe6;border-radius:10px;border:3px dashed #ffd93d;transition:all .3s ease}.answer-display.empty-answer{color:#ffd93d}.answer-display.correct-answer{color:#1a472a;background:linear-gradient(135deg,#90ee90,#98fb98);border:3px solid #228B22;animation:correctPop .3s ease}.answer-display.wrong-answer{color:#f44;background:linear-gradient(135deg,#ffb3b3,#ff8080);border:3px solid #ff0000;animation:shake .3s ease}@keyframes correctPop{0%{transform:scale(1)}50%{transform:scale(1.3)}to{transform:scale(1)}}@keyframes shake{0%,to{transform:translate(0)}25%{transform:translate(-5px)}75%{transform:translate(5px)}}.feedback-overlay{position:absolute;top:55%;left:50%;transform:translate(-50%,-50%);width:80px;height:80px;display:flex;align-items:center;justify-content:center;border-radius:50%;z-index:50;animation:feedbackPop .4s ease}@keyframes feedbackPop{0%{transform:translate(-50%,-50%) scale(0)}50%{transform:translate(-50%,-50%) scale(1.3)}to{transform:translate(-50%,-50%) scale(1)}}.feedback-overlay.correct-overlay{background:linear-gradient(135deg,#90ee90,#98fb98);box-shadow:0 0 30px #90ee90cc}.feedback-overlay.wrong-overlay{background:linear-gradient(135deg,#ffb3b3,#ff8080);box-shadow:0 0 30px #ff8080cc}.feedback-overlay .feedback-icon{font-size:2.5rem}.keypad-4col{position:fixed;bottom:15px;left:50%;transform:translate(-50%);width:90%;max-width:360px;z-index:10}.keypad-row{display:flex;justify-content:center;gap:6px;margin-bottom:6px}.keypad-row.bottom-row{gap:6px}.keypad-row button{flex:1;padding:14px 0;font-size:1.5rem;font-weight:700;background:linear-gradient(145deg,#fff,#f0f0f0);border:2px solid #ddd;border-radius:10px;cursor:pointer;transition:all .1s;box-shadow:0 3px 6px #0000001a}.keypad-row button:active{transform:scale(.95);background:#e0e0e0}.keypad-row .delete-btn{background:linear-gradient(145deg,#fff0f0,#ffe0e0);border-color:#ffb3b3;color:#ff6b6b}.keypad-row .delete-btn:active{background:#fcc}.keypad-row.bottom-row button:last-child{flex:1.5}.result-screen{position:absolute;top:0;left:0;width:100%;height:100%;display:flex;align-items:center;justify-content:center;background:#000c;z-index:100;padding:20px}.result-content{background:linear-gradient(135deg,#1a472a,#2d5a3f);padding:30px;border-radius:25px;text-align:center;box-shadow:0 20px 50px #0000004d;max-width:380px;width:100%}.result-avatar{font-size:4.5rem;margin-bottom:10px;animation:bounce 1s ease infinite}.result-content h2{color:#ffd93d;font-size:1.8rem;margin-bottom:20px}.result-stats{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin-bottom:20px}.result-item{background:#ffffff1a;padding:12px;border-radius:12px}.result-item .label{display:block;font-size:.85rem;color:#aaa;margin-bottom:5px}.result-item .value{font-size:1.3rem;color:#fff;font-weight:700}.result-item .score-value{color:#ffd93d;font-size:1.6rem}.grade{padding:15px;border-radius:15px;font-size:1.3rem;margin-bottom:20px;animation:gradeGlow 2s ease infinite}@keyframes gradeGlow{0%,to{box-shadow:0 0 20px currentColor}50%{box-shadow:0 0 40px currentColor}}.grade-s{background:linear-gradient(135deg,gold,#fa0);color:#fff}.grade-a{background:linear-gradient(135deg,#4caf50,#8bc34a);color:#fff}.grade-b{background:linear-gradient(135deg,#2196f3,#03a9f4);color:#fff}.grade-c{background:linear-gradient(135deg,#ff9800,#ffc107);color:#fff}.result-actions{display:flex;gap:15px;justify-content:center}.restart-btn,.history-btn-small{padding:12px 25px;font-size:1.1rem;border:none;border-radius:20px;color:#fff;cursor:pointer;font-weight:700}.restart-btn{background:linear-gradient(45deg,#ff6b6b,#ee5a5a)}.history-btn-small{background:linear-gradient(45deg,#1e90ff,#00bfff)}.result-actions button:hover{transform:scale(1.05)}.history-modal{position:fixed;top:0;left:0;width:100%;height:100%;background:#000c;z-index:200;display:flex;align-items:center;justify-content:center;padding:20px}.history-content{background:linear-gradient(135deg,#1a472a,#2d5a3f);border-radius:25px;padding:25px;max-width:450px;width:100%;max-height:80vh;overflow-y:auto;box-shadow:0 20px 50px #00000080}.history-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}.history-header h2{color:#ffd93d;font-size:1.5rem}.close-btn{width:35px;height:35px;border-radius:50%;background:#fff3;border:none;color:#fff;font-size:1.2rem;cursor:pointer}.history-summary{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin-bottom:20px}.summary-item{background:#ffffff1a;padding:12px;border-radius:12px;text-align:center}.summary-item .label{display:block;font-size:.85rem;color:#aaa;margin-bottom:5px}.summary-item .value{font-size:1.4rem;color:#fff;font-weight:700}.summary-item .value.highlight{color:#ffd93d}.grade-stats{display:flex;gap:10px;margin-bottom:20px}.grade-item{flex:1;padding:10px;border-radius:10px;text-align:center;font-size:.9rem;color:#fff;font-weight:700}.grade-item.grade-s{background:linear-gradient(135deg,gold,#fa0)}.grade-item.grade-a{background:linear-gradient(135deg,#4caf50,#8bc34a)}.grade-item.grade-b{background:linear-gradient(135deg,#2196f3,#03a9f4)}.grade-item.grade-c{background:linear-gradient(135deg,#ff9800,#ffc107)}.history-list h3{color:#fff;font-size:1.1rem;margin-bottom:12px}.no-records{color:#aaa;text-align:center;padding:20px;background:#ffffff0d;border-radius:12px}.history-item{background:#ffffff1a;border-radius:12px;padding:12px;margin-bottom:10px;border-left:4px solid}.history-item.grade-s{border-color:gold}.history-item.grade-a{border-color:#4caf50}.history-item.grade-b{border-color:#2196f3}.history-item.grade-c{border-color:#ff9800}.record-header{display:flex;justify-content:space-between;margin-bottom:8px}.record-date{color:#aaa;font-size:.85rem}.record-grade{font-weight:700;color:#ffd93d}.record-details{display:flex;gap:15px;color:#fff;font-size:.9rem}.clear-history-btn{width:100%;margin-top:20px;padding:12px;background:#ff6b6b4d;border:2px solid #ff6b6b;border-radius:12px;color:#ff6b6b;font-size:1rem;cursor:pointer}.clear-history-btn:hover{background:#ff6b6b80}.music-btn{position:absolute;bottom:20px;right:20px;width:50px;height:50px;border-radius:50%;background:linear-gradient(135deg,#ffd93d,#fa0);border:none;font-size:1.3rem;cursor:pointer;z-index:100;box-shadow:0 3px 15px #0003}.music-btn:active{transform:scale(.9)}@media (max-width: 480px){.game-title h1{font-size:1.1rem}.title-decoration{font-size:1.3rem}.question-formula{font-size:2.2rem}.mode-btn{padding:10px 12px;font-size:.9rem}.start-buttons{flex-direction:column}.result-stats{grid-template-columns:repeat(2,1fr)}.grade-stats{flex-wrap:wrap}}