:root{--color-primary:#5a6268;--color-black:#111;--color-success:#22c55e;--color-error:#ef4444;--color-bg:#f5f5f5;--color-surface:#ffffff;--color-text:#1f2937;--color-border:#e5e7eb}*{box-sizing:border-box}body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:#ddd;color:var(--color-text)}.container{max-width:600px;margin:0 auto}.header{text-align:center;margin-bottom:20px}.header h1{margin:0;font-size:2em}.header p{margin:5px 0 0;color:#6B7280}.stats{display:grid;grid-template-columns:repeat(3,1fr);grid-gap:10px;gap:10px;margin-bottom:20px}.stat-item{background:var(--color-surface);padding:10px;border-radius:8px;border:1px solid var(--color-border);text-align:center}.stat-label{font-size:.8em;opacity:.7;margin-bottom:4px}.stat-value{font-size:1.2em;font-weight:600;color:var(--color-primary)}.sudoku-board{background:white;padding:1px;border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,.1);margin-bottom:10px;display:flex;justify-content:center}.sudoku-grid{display:grid;grid-template-columns:repeat(9,1fr);width:100%;aspect-ratio:1;border:3px solid var(--color-primary)}.sudoku-board-normal .sudoku-grid{background-color:#EFF6FF;border-color:#3B82F6}.sudoku-board-candidate .sudoku-grid{background-color:#F0FDF4;border-color:#22C55E}.sudoku-cell{position:relative;display:flex;align-items:center;justify-content:center;border:1px solid #ddd;background-color:#FFFFFF;cursor:pointer;overflow:hidden}.sudoku-cell:nth-child(3n):not(:nth-child(9n)){border-right:2px solid var(--color-black)}.sudoku-grid>div:nth-child(n+19):nth-child(-n+27),.sudoku-grid>div:nth-child(n+46):nth-child(-n+54){border-bottom:2px solid var(--color-black)}.sudoku-cell.selected{background-color:#BFDBFE}.sudoku-board-candidate .sudoku-cell.selected{background-color:#BBF7D0}.given-value,.sudoku-cell .given-value{font-size:20px;font-weight:700;width:100%;height:100%;display:flex;align-items:center;justify-content:center}.sudoku-cell.hint-primary{background-color:#FBBF24!important;box-shadow:inset 0 0 0 2px #F59E0B!important}.sudoku-cell.hint-affected{background-color:#FEE2E2!important;box-shadow:inset 0 0 0 1px #FCA5A5!important}.candidates-view{display:grid;grid-template-columns:repeat(3,1fr);width:100%;height:100%}.candidate-mini{display:flex;align-items:center;justify-content:center;width:100%;height:100%;font-size:10px;font-weight:700;color:#111;line-height:1}.mode-toggle{display:flex;gap:10px;margin-bottom:15px}.mode-toggle button{flex:1 1;padding:10px;border-radius:6px;cursor:pointer;font-weight:600;border:2px solid #e5e7eb;background:white;color:#6b7280}.sudoku-board-normal~.mode-toggle .mode-btn-normal{background-color:#4172bb;color:white;border-color:#3B82F6}.sudoku-board-candidate~.mode-toggle .mode-btn-candidate{background-color:#5a6268;color:white;border-color:#22C55E}.numpad{display:grid;grid-template-columns:repeat(3,1fr);grid-gap:10px 10px;gap:10px 10px;background:rgba(0,0,0,.05);padding:10px;border-radius:12px}.numpad-btn{width:100%;margin-top:7px;padding:15px 0;background:#4172bb;color:white;border:none;border-radius:6px;font-size:1.2em;font-weight:700;cursor:pointer;display:flex;align-items:center;justify-content:center}.numpad-candidate .numpad-btn{background-color:#5a6268}.numpad-btn:active{transform:scale(.95)}.end-controls,.game-controls{display:grid;grid-template-columns:1fr 1fr;grid-gap:10px;gap:10px;margin-top:15px}.btn{padding:12px;border:none;border-radius:8px;font-weight:600;cursor:pointer;font-size:.9em}.btn-primary{background:#3B82F6;color:white}.btn-info{background:#60A5FA;color:white}.feedback{position:fixed;top:20px;left:50%;transform:translateX(-50%) translateY(-20px);padding:10px 20px;border-radius:20px;font-weight:700;opacity:0;transition:all .3s ease;pointer-events:none;z-index:9999;white-space:nowrap;box-shadow:0 4px 6px rgba(0,0,0,.1)}.feedback.show{opacity:1;transform:translateX(-50%) translateY(0)}.feedback.success{background:#22c55e;color:white}.feedback.error{background:#ef4444;color:white}.feedback.warning{background:#F59E0B;color:white}.feedback.info{background:#3B82F6;color:white}@media (max-width:480px){.header h1{font-size:1.5em}.given-value,.sudoku-cell .given-value{font-size:25px}.candidate-mini{font-size:10px}.stats{gap:5px}.stat-value{font-size:1em}}