body {
    font-family: Arial, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    margin: 0;
    background-color: #f0f0f0;
}

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

.controls {
    margin-bottom: 20px;
}

#startButton {
    padding: 10px 20px;
    font-size: 18px;
    cursor: pointer;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}

#startButton:hover {
    background-color: #45a049;
}

.game-board {
    display: grid;
    border: 2px solid #333;
    background-color: #ccc;
}

.cell {
    width: 40px; /* スマートフォン対応のため小さめに */
    height: 40px;
    background-color: #ddd;
    border: 1px solid #999;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: bold;
    cursor: pointer;
    user-select: none; /* テキスト選択を防ぐ */
}

.cell.revealed {
    background-color: #eee;
    cursor: default;
}

.cell.bear {
    background-color: #f44336;
    color: white;
}

.cell.number-1 { color: blue; }
.cell.number-2 { color: green; }
.cell.number-3 { color: red; }
.cell.number-4 { color: purple; }
.cell.number-5 { color: maroon; }
.cell.number-6 { color: teal; }
.cell.number-7 { color: black; }
.cell.number-8 { color: gray; }

/* スマートフォン向けの調整 */
@media (max-width: 600px) {
    .cell {
        width: 35px;
        height: 35px;
        font-size: 18px;
    }
    h1 {
        font-size: 24px;
    }
    #startButton {
        font-size: 16px;
        padding: 8px 15px;
    }
}