:root{font-family:system-ui,Avenir,Helvetica,Arial,sans-serif;line-height:1.5;font-weight:400;color-scheme:light dark;color:#ffffffde;background-color:#242424;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}a{font-weight:500;color:#646cff;text-decoration:inherit}a:hover{color:#535bf2}body{margin:0;display:flex;place-items:center;min-width:320px;min-height:100vh}h1{font-size:3.2em;line-height:1.1}button{border-radius:8px;border:1px solid transparent;padding:.6em 1.2em;font-size:1em;font-weight:500;font-family:inherit;background-color:#1a1a1a;cursor:pointer;transition:border-color .25s}button:hover{border-color:#646cff}button:focus,button:focus-visible{outline:4px auto -webkit-focus-ring-color}@media(prefers-color-scheme:light){:root{color:#213547;background-color:#fff}a:hover{color:#747bff}button{background-color:#f9f9f9}}:root[data-theme=dark]{--primary-color: #0ea5e9;--secondary-color: #0284c7;--bg-color: #0c1e2e;--surface-color: #0f2739;--text-color: #e0f2fe;--text-muted: #7dd3fc;--border-color: #164e63;--cell-bg: #082f49;--cell-hover: #0e4a6b;--cell-selected: #075985;--incorrect-color: #f87171;--correct-color: #34d399;--initial-color: rgba(14, 165, 233, .3)}:root[data-theme=light]{--primary-color: #0ea5e9;--secondary-color: #0284c7;--bg-color: #ffffff;--surface-color: #f9f9f9;--text-color: #213547;--text-muted: #666;--border-color: #ccc;--cell-bg: #fff;--cell-hover: #f5f5f5;--cell-selected: #e3e8ff;--incorrect-color: #ff0000;--initial-color: rgba(100, 108, 255, .15)}*{box-sizing:border-box}body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Fira Sans,Droid Sans,Helvetica 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var(--border-color)}button{background-color:var(--primary-color);color:#fff;border:none;padding:.75rem 1.5rem;font-size:1rem;font-weight:500;border-radius:8px;cursor:pointer;transition:all .3s ease;font-family:inherit}button:hover:not(:disabled){background-color:var(--secondary-color);transform:translateY(-2px);box-shadow:0 4px 12px #646cff66}button:active:not(:disabled){transform:translateY(0)}button:disabled{opacity:.5;cursor:not-allowed}button.active{background-color:var(--secondary-color);box-shadow:0 0 0 3px #646cff4d}.difficulty-buttons{display:flex;flex-direction:column;gap:.5rem;margin-bottom:1rem}.difficulty-buttons button{flex:1}.controls-row{display:flex;align-items:center;gap:.5rem;margin-bottom:.5rem;flex-wrap:wrap}.checkbox-label{display:flex;align-items:center;gap:.5rem;cursor:pointer;padding:.25rem;border-radius:4px;transition:background-color .2s;-webkit-user-select:none;user-select:none}.checkbox-label:hover{background-color:var(--cell-hover)}.checkbox-label 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strong{color:var(--primary-color)}.board{display:inline-block;background-color:var(--border-color);padding:2px;border-radius:8px;box-shadow:0 8px 32px #0000004d}.board-row{display:flex}.cell{width:60px;height:60px;background-color:var(--cell-bg);border:1px solid var(--border-color);display:flex;align-items:center;justify-content:center;cursor:pointer;font-size:1.5rem;font-weight:600;transition:all .2s ease;position:relative;-webkit-user-select:none;user-select:none}.cell:hover{background-color:var(--cell-hover)}.cell.selected{background-color:var(--cell-selected);box-shadow:inset 0 0 0 2px var(--primary-color)}.cell.initial{background-color:var(--initial-color);font-weight:700}.cell.initial .cell-value{color:var(--primary-color)}.cell.incorrect{color:var(--incorrect-color);animation:shake .5s}@keyframes shake{0%,to{transform:translate(0)}25%{transform:translate(-5px)}75%{transform:translate(5px)}}.cell.right-border{border-right:3px solid var(--border-color)}.cell.bottom-border{border-bottom:3px solid var(--border-color)}.cell-value{font-size:1.8rem}.notes{display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:repeat(3,1fr);width:100%;height:100%;padding:2px;gap:1px}.note{display:flex;align-items:center;justify-content:center;font-size:.7rem;color:var(--text-muted);font-weight:500}.board-section{display:flex;flex-direction:column;gap:2rem;align-items:center}.keypad{display:grid;grid-template-columns:repeat(5,1fr);gap:.5rem;width:100%;max-width:540px;margin-top:1rem}.keypad-button{font-size:1.2rem;font-weight:600;padding:.5rem;min-width:50px;height:50px}.keypad-clear{background-color:#f44;padding:.5rem;grid-column:span 1}.keypad-clear:hover:not(:disabled){background-color:red}.start-page{max-width:600px;margin:0 auto;padding:2rem;text-align:center}.start-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:3rem}.start-header h1{font-size:3rem;margin:0;color:var(--primary-color)}.theme-toggle{font-size:1.5rem;padding:.5rem;background:transparent;border:none;cursor:pointer;min-width:auto}.difficulty-selection{margin-bottom:3rem}.difficulty-selection h2{margin-bottom:1.5rem;color:var(--text-color)}.difficulty-buttons-start{display:flex;flex-direction:column;gap:1rem}.difficulty-btn{padding:1.5rem;font-size:1.3rem;font-weight:600;border-radius:8px;border:2px solid var(--border-color);background-color:var(--surface-color);color:var(--text-color);cursor:pointer;transition:all .2s}.difficulty-btn:hover{transform:translateY(-2px);border-color:var(--primary-color);box-shadow:0 4px 12px #646cff4d}.difficulty-btn.easy:hover{border-color:#4ade80;box-shadow:0 4px 12px #4ade804d}.difficulty-btn.medium:hover{border-color:#fbbf24;box-shadow:0 4px 12px #fbbf244d}.difficulty-btn.hard:hover{border-color:#f87171;box-shadow:0 4px 12px #f871714d}.start-instructions{text-align:left;background-color:var(--surface-color);padding:1.5rem;border-radius:8px;border:1px solid var(--border-color)}.start-instructions h3{margin-top:0;color:var(--text-color)}.start-instructions ul{color:var(--text-muted);line-height:1.8}.new-game-section{position:relative;margin-bottom:1rem}.new-game-toggle{width:100%;margin-bottom:.5rem}.difficulty-menu{display:flex;flex-direction:column;gap:.5rem}.difficulty-menu button{padding:.5rem}@media(max-width:768px){.game-container{flex-direction:column;gap:2rem}.controls{max-width:100%}.keypad-button{min-width:40px;height:45px;font-size:1.1rem;padding:.4rem}.keypad-clear{min-width:40px;height:45px}.start-header h1{font-size:2rem}.difficulty-btn{padding:1.2rem;font-size:1.1rem}.cell{width:40px;height:40px;font-size:1.2rem}.cell-value{font-size:1.4rem}.note{font-size:.5rem}.controls-header h1{font-size:2rem}.app{padding:1rem}}@media(max-width:480px){.cell{width:35px;height:35px;font-size:1rem}.cell-value{font-size:1.2rem}.note{font-size:.45rem}button{padding:.6rem 1rem;font-size:.9rem}.game-info{flex-direction:column;gap:.5rem}}