body {
    font-family: Arial, "Microsoft JhengHei", sans-serif;
    background: #f5f7fb;
    margin: 0;
    padding: 20px;
}

.game-container {
    max-width: 600px;
    margin: 0 auto;
    background: #ffffff;
    border-radius: 16px;
    padding: 24px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

h2,
h3 {
    text-align: center;
}

.board {
    margin-top: 20px;
}

.puzzle-row {
    display: flex;
    justify-content: center;
    margin-bottom: 10px;
}

.cell {
    width: 64px;
    height: 64px;
    border: 2px solid #333;
    margin-right: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: bold;
    background: #ffffff;
    border-radius: 8px;
}

.blank {
    background: #fff3cd;
    cursor: pointer;
}

.options {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin: 16px 0;
}

.option {
    width: 64px;
    height: 56px;
    border: 2px solid #2f80ed;
    background: #ffffff;
    color: #2f80ed;
    font-size: 22px;
    font-weight: bold;
    border-radius: 10px;
    cursor: pointer;
}

    .option.selected {
        background: #2f80ed;
        color: #ffffff;
    }

.actions {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-top: 20px;
}

    .actions button {
        padding: 10px 20px;
        font-size: 16px;
        border: 0;
        border-radius: 8px;
        cursor: pointer;
        background: #333;
        color: #ffffff;
    }

.message {
    text-align: center;
    margin-top: 20px;
    font-size: 20px;
    font-weight: bold;
}