body {
    margin: 0;
    background: #111827;
    color: white;
    font-family: Arial, sans-serif;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}


.game-container {
    text-align: center;
}


#board {
    display: grid;
    grid-template-columns: repeat(9, 40px);
    margin: 20px auto;
    width: fit-content;
}


.cell {
    width: 40px;
    height: 40px;
    border: 1px solid #64748b;
    background: #1e293b;
    color: white;
    font-size: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
}


.fixed {
    background: #334155;
    cursor: default;
}


.selected {
    background: #2563eb;
}


.numbers button,
#newGame {
    margin: 4px;
    padding: 10px 15px;
    border: none;
    border-radius: 8px;
    background: #22c55e;
    color: white;
    cursor: pointer;
    font-size: 16px;
}


.numbers button:hover,
#newGame:hover {
    background: #16a34a;
}