/* 全体のリセットと共通設定 */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    color: #333;
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem 1rem;
    background-color: #fafafa;
}

/* ヘッダー・ナビゲーション */
header {
    border-bottom: 2px solid #eaeaea;
    padding-bottom: 1rem;
    margin-bottom: 2rem;
}
nav a {
    color: #0070f3;
    text-decoration: none;
    margin-right: 1rem;
}
nav a:hover { text-decoration: underline; }

/* 記事の装飾 */
article { background: white; padding: 2rem; border-radius: 8px; box-shadow: 0 2px 4px rgba(0,0,0,0.05); }
h1 { font-size: 2rem; color: #111; }
h2 { font-size: 1.5rem; color: #222; margin-top: 2rem; border-left: 4px solid #0070f3; padding-left: 0.5rem; }
time { color: #666; font-size: 0.9rem; }

/* フッター */
footer { margin-top: 4rem; text-align: center; color: #999; font-size: 0.8rem; }