*{margin:0;padding:0;box-sizing:border-box}body{font-family:'Segoe UI',Tahoma,Geneva,Verdana,sans-serif;background:linear-gradient(135deg,#667eea 0,#764ba2 100%);min-height:100vh;display:flex;flex-direction:column;justify-content:center;align-items:center;padding:20px;color:#fff;transition:all .3s ease;box-sizing:border-box}.dark{background:linear-gradient(135deg,#2c3e50 0,#34495e 100%);color:#ecf0f1}h2{color:#fff;margin-bottom:20px;font-size:2.5rem;text-shadow:2px 2px 4px rgba(0,0,0,.3);text-align:center;font-weight:700}.title-container{align-items:center;gap:15px;margin-bottom:20px}.dark h2{color:#ecf0f1;text-shadow:2px 2px 4px rgba(0,0,0,.5)}#controls{width:100%;max-width:600px;margin-bottom:15px;display:flex;flex-direction:column;align-items:center}#top-row{display:flex;justify-content:center;align-items:center;flex-wrap:wrap;gap:12px;padding:8px 0;width:100%}#game-info,#grid-controls{display:flex;align-items:center;gap:8px}.control-select{background:0 0;border:1px solid rgba(255,255,255,.3);border-radius:6px;padding:6px 10px;font-size:13px;font-weight:600;cursor:pointer;transition:all .3s ease;outline:0;color:#000}.control-select:hover{border-color:#667eea;background:rgba(255,255,255,.1);box-shadow:0 4px 12px rgba(102,126,234,.2)}.dark .control-select{background:0 0;border:1px solid rgba(255,255,255,.2);color:#ecf0f1}.control-btn{background:0 0;border:1px solid rgba(255,255,255,.3);color:#fff;padding:6px 8px;border-radius:6px;cursor:pointer;font-size:16px;transition:all .3s ease;font-weight:600;min-width:35px;height:35px;display:flex;align-items:center;justify-content:center}.control-btn:hover{background:rgba(255,255,255,.1);transform:translateY(-1px);box-shadow:0 4px 12px rgba(0,0,0,.1)}.control-btn.primary{background:linear-gradient(135deg,#667eea 0,#764ba2 100%);border:1px solid rgba(102,126,234,.5);box-shadow:0 2px 8px rgba(102,126,234,.2)}.control-btn.primary:hover{background:linear-gradient(135deg,#5a6fd8 0,#6a4190 100%);box-shadow:0 4px 12px rgba(102,126,234,.3)}.hint-btn{background:linear-gradient(135deg,#f093fb 0,#f5576c 100%);border:1px solid rgba(240,147,251,.5);font-size:12px!important;gap:2px;position:relative}.hint-btn:hover{background:linear-gradient(135deg,#ee88f7 0,#f34a5a 100%);box-shadow:0 4px 12px rgba(240,147,251,.3)}.hint-counter{position:absolute;top:-5px;right:-5px;background:linear-gradient(135deg,#ff4757 0,#ff3742 100%);color:#fff;border-radius:10px;padding:2px 6px;font-size:10px;font-weight:700;min-width:16px;text-align:center;border:1px solid #fff;box-shadow:0 2px 4px rgba(0,0,0,.2)}.solve-btn{background:linear-gradient(135deg,#ff6b6b 0,#e55353 100%);border:1px solid rgba(255,107,107,.5)}.solve-btn:hover{background:linear-gradient(135deg,#ff5252 0,#d32f2f 100%);box-shadow:0 4px 12px rgba(255,107,107,.3)}.control-btn:disabled{opacity:.5;cursor:not-allowed;transform:none!important}.dark .control-btn{background:0 0;border:1px solid rgba(255,255,255,.2)}.info-display{font-size:14px;font-weight:600;padding:6px 10px;background:0 0;border-radius:8px;color:#fff;border:1px solid rgba(255,255,255,.3)}.dark .info-display{background:0 0;color:#ecf0f1;border:1px solid rgba(255,255,255,.2)}#game-container{display:flex;justify-content:center;align-items:center;margin:15px 0;width:100%}#sudoku-grid{display:grid;gap:2px;background:#2c3e50;padding:15px;border-radius:12px;box-shadow:0 8px 32px rgba(0,0,0,.3);border:2px solid rgba(255,255,255,.15)}.dark #sudoku-grid{background:#1a252f;border:2px solid rgba(255,255,255,.1);box-shadow:0 8px 32px rgba(0,0,0,.5)}.sudoku-cell{width:45px;height:45px;background:linear-gradient(135deg,#ecf0f1 0,#bdc3c7 100%);display:flex;justify-content:center;align-items:center;font-weight:700;font-size:18px;cursor:pointer;user-select:none;border-radius:4px;transition:all .2s ease;border:1px solid #95a5a6;border-top-color:#fff;border-left-color:#fff;border-bottom-color:#7f8c8d;border-right-color:#7f8c8d;box-shadow:0 3px 6px rgba(0,0,0,.15);color:#2c3e50}.sudoku-cell:hover{background:linear-gradient(135deg,#f8f9fa 0,#d5dbdb 100%);transform:scale(1.02);box-shadow:0 4px 12px rgba(0,0,0,.2)}.sudoku-cell.filled{background:linear-gradient(135deg,#3498db 0,#2980b9 100%);color:#fff;font-weight:900;cursor:default}.sudoku-cell.filled:hover{transform:none;background:linear-gradient(135deg,#3498db 0,#2980b9 100%)}.sudoku-cell.selected{background:linear-gradient(135deg,#f39c12 0,#e67e22 100%);color:#fff;box-shadow:0 0 15px rgba(243,156,18,.6)}.sudoku-cell.invalid{background:linear-gradient(135deg,#e74c3c 0,#c0392b 100%);color:#fff;animation:shake .5s ease-in-out}.sudoku-cell.hint{background:linear-gradient(135deg,#27ae60 0,#2ecc71 100%);color:#fff;animation:pulse 1s ease-in-out}.sudoku-cell.correct{background:linear-gradient(135deg,#27ae60 0,#2ecc71 100%);color:#fff;font-weight:700}.sudoku-cell.border-top{border-top:3px solid #2c3e50}.sudoku-cell.border-bottom{border-bottom:3px solid #2c3e50}.sudoku-cell.border-left{border-left:3px solid #2c3e50}.sudoku-cell.border-right{border-right:3px solid #2c3e50}@keyframes shake{0%,100%{transform:translateX(0)}25%{transform:translateX(-3px)}75%{transform:translateX(3px)}}@keyframes pulse{0%,100%{transform:scale(1)}50%{transform:scale(1.1)}}#bottom-controls{display:flex;justify-content:center;align-items:center;width:100%;max-width:600px;padding:8px 0;margin-top:15px}.toggle-group{display:flex;background:0 0;border-radius:6px;padding:2px;gap:6px;border:1px solid rgba(255,255,255,.2)}#number-pad{display:grid;grid-template-columns:repeat(6,1fr);gap:6px;margin:20px auto;max-width:300px;width:100%;justify-self:center}.number-btn{width:40px;height:40px;background:linear-gradient(135deg,#ecf0f1 0,#bdc3c7 100%);border:1px solid #95a5a6;border-radius:6px;font-size:16px;font-weight:700;color:#2c3e50;cursor:pointer;transition:all .2s ease;display:flex;align-items:center;justify-content:center}.number-btn:hover{background:linear-gradient(135deg,#f8f9fa 0,#d5dbdb 100%);transform:translateY(-2px);box-shadow:0 4px 12px rgba(0,0,0,.2)}.number-btn.selected{background:linear-gradient(135deg,#667eea 0,#764ba2 100%);color:#fff;box-shadow:0 0 15px rgba(102,126,234,.5)}.erase-btn{background:linear-gradient(135deg,#e74c3c 0,#c0392b 100%);color:#fff}.erase-btn:hover{background:linear-gradient(135deg,#ff6b6b 0,#e55353 100%)}#gamewin{position:fixed;top:0;left:0;width:100%;height:100%;background:rgba(0,0,0,.8);display:flex;justify-content:center;align-items:center;z-index:1000;backdrop-filter:blur(5px)}.gamewin-content{background:linear-gradient(135deg,#56ab2f 0,#a8e6cf 100%);padding:40px;border-radius:20px;text-align:center;box-shadow:0 20px 60px rgba(0,0,0,.3);border:2px solid rgba(255,255,255,.2);max-width:400px;width:90%}.gamewin-content h3{color:#fff;margin-bottom:15px;font-size:2rem}.gamewin-content p{color:rgba(255,255,255,.9);margin-bottom:15px;font-size:1.1rem;line-height:1.5}.gamewin-button-container{display:flex;justify-content:center;margin-top:20px}.gamewin-btn{background:rgba(255,255,255,.2);border:2px solid rgba(255,255,255,.3);color:#fff;padding:12px 25px;border-radius:10px;font-size:16px;font-weight:600;cursor:pointer;transition:all .3s ease}.gamewin-btn:hover{background:rgba(255,255,255,.3);transform:translateY(-2px);box-shadow:0 8px 25px rgba(0,0,0,.2)}.hidden{display:none!important}@media (max-width:768px){body{padding:15px}h2{font-size:2rem;margin-bottom:15px}#top-row{flex-direction:column;gap:10px}#bottom-controls{flex-direction:column;gap:15px}.sudoku-cell{width:35px;height:35px;font-size:16px}.number-btn{width:35px;height:35px;font-size:14px}#number-pad{max-width:200px}}@media (max-width:480px){.sudoku-cell{width:30px;height:30px;font-size:14px}.number-btn{width:32px;height:32px;font-size:12px}#number-pad{max-width:180px}h2{font-size:1.5rem}}