body {
    font-family: 'Arial', sans-serif;
    background-color: #000;
    text-align: center;
    margin: 0;
    padding: 0;
}

.container {
    max-width: 310px;
    margin: 20px auto;
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    padding: 20px;
    border-radius: 5px;
}

h1 {
    font-size: 24px;
    color: #333;
    margin-bottom: 20px;
}

#sudoku-select {
    font-size: 16px;
    padding: 10px;
    width: 100%;
    margin-bottom: 20px;
    border: 1px solid #ccc;
    border-radius: 5px;
    background-color: #f8f8f8;
    color: #333;
}

#user {
    background-color: #004000;
    color: #fff;
}

#sudoku-board {
    display: grid;
    grid-template-columns: repeat(9, 34px);
    gap: 0;
    margin: 20px 0;
    border: 2px solid #333;
}

.cell {
    width: 34px;
    height: 34px;
    background-color: #eee;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 16px;
    font-weight: bold;
    border: 1px solid #999;
    color: #333;
    margin: 0;
    box-sizing: border-box;
}

button {
    padding: 10px 20px;
    background-color: #007BFF;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    margin: 10px;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #0056b3;
}

button:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

#solve-button {
    background-color: #28a745;
}

#solve-button:hover {
    background-color: #1e7e34;
}

#new-game-button {
    background-color: #dc3545;
}

#new-game-button:hover {
    background-color: #bd2130;
}

html, body {
  height: 100%;
}

body {
    display: flex;
    align-items: center;
    justify-content: center;
}

.message {
    margin-top: 20px;
    font-size: 18px;
    color: #fff;
    background-color: #000;
}