body {
    font-family: sans-serif;
    margin: 0;
    padding: 0;
    background: #f9f9f9;
}

header {
    background: #333;
    padding: 10px;
}
nav a {
    color: white;
    margin: 0 10px;
    text-decoration: none;
}
nav a:hover {
    text-decoration: underline;
}

main {
    padding: 20px;
}

/* フェードインアニメーション */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeUp 0.6s ease forwards;
}

@keyframes fadeUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}