/* 全体のレイアウト */
body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    font-family: 'Helvetica Neue', Arial, sans-serif;
    background-color: #f0f0f0;
    transition: background-color 0.5s ease;
}

.container {
    text-align: center;
}

/* ボタンのデザイン */
button {
    padding: 15px 30px;
    font-size: 1.2rem;
    cursor: pointer;
    border: none;
    border-radius: 8px;
    background-color: #333;
    color: white;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.1s, background-color 0.3s;
}

button:hover {
    background-color: #555;
}

button:active {
    transform: scale(0.95);
}