body {
    font-family: 'Arial', sans-serif;
    background-color: #003e50;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    margin: 0;
}

#puzzle-board {
    display: grid;
    grid-template-columns: repeat(4, 100px);
    grid-template-rows: repeat(4, 100px);
    width: 400px;
    height: 400px;
    margin: 50px auto;
    border: 5px solid #34495e;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
    position: relative;
}

.puzzle-tile {
    width: 100px;
    height: 100px;
    background-color: #3498db;
    color: #ecf0f1;
    font-size: 2em;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid #2c3e50;
    cursor: pointer;
    transition: all 0.2s ease-in-out;
    position: absolute;
}

.puzzle-tile.empty {
    background-color: #34495e;
    color: transparent;
    cursor: default;
}

.puzzle-tile:not(.empty):hover {
    background-color: #2980b9;
}

button#reset-button {
    background-color: #e74c3c;
    color: white;
    padding: 10px 20px;
    margin-top: 20px;
    border: none;
    border-radius: 5px;
    font-size: 1.2em;
    cursor: pointer;
    transition: background-color 0.2s ease-in-out;
}

button#reset-button:hover {
    background-color: #c0392b;
}

#status-display {
    text-align: center;
    color: #ffffff;
    font-size: 2em;
    margin-bottom: 20px;
}

@media (max-width: 600px) {
    body {
        min-height: auto; /* モバイルでのスクロールを可能にする */
    }

    #status-display {
        font-size: 2em; /* ステータス表示のフォントサイズを調整 */
    }

    button#reset-button {
        padding: 8px 15px;
        font-size: 1em;
    }
}