/* 全体のリセットと共通設定 */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: #0d0f14;
    color: #e2e8f0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    line-height: 1.7;
    padding: 2rem 1rem;
}

.container {
    max-width: 680px;
    margin: 0 auto;
}

/* ヘッダー */
header {
    margin-bottom: 3rem;
    border-bottom: 1px solid #1e293b;
    padding-bottom: 1.5rem;
}

header h1 a {
    color: #4facfe;
    text-decoration: none;
    font-size: 1.8rem;
    font-weight: 700;
}

/* 記事一覧 (index.html用) */
.post-list {
    list-style: none;
}

.post-item {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: #161b26;
    border-radius: 8px;
    border-left: 4px solid #7f00ff;
    transition: transform 0.2s ease;
}

.post-item:hover {
    transform: translateX(4px);
}

.post-date {
    font-size: 0.85rem;
    color: #94a3b8;
    display: block;
    margin-bottom: 0.5rem;
}

.post-title a {
    color: #e2e8f0;
    text-decoration: none;
    font-size: 1.3rem;
    font-weight: 600;
}

.post-title a:hover {
    color: #00f2fe;
}

/* 記事本文 (day1.html用) */
.article-header {
    margin-bottom: 2rem;
}

.article-title {
    font-size: 2rem;
    color: #ffffff;
    line-height: 1.3;
    margin-bottom: 0.5rem;
}

.article-content p {
    margin-bottom: 1.5rem;
}

.link {
    text-decoration: none;
    color: #7f00ff
}

.back-link {
    display: inline-block;
    margin-top: 3rem;
    color: #7f00ff;
    text-decoration: none;
    font-weight: 500;
}

.back-link:hover {
    color: #00f2fe;
}

/* フッター */
footer {
    margin-top: 4rem;
    text-align: center;
    font-size: 0.8rem;
    color: #64748b;
}