/* ドキュメント用スタイル */
:root {
    --primary-color: #4a90e2;
    --text-color: #333;
    --bg-color: #f5f5f5;
    --white: #fff;
    --border-color: #e0e0e0;
    --link-color: #2563eb;
    --link-hover: #1d4ed8;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: var(--bg-color);
}

/* ヘッダー */
header {
    background: var(--white);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    text-align: center;
    margin-bottom: 1rem;
}

header h1 a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1.5rem;
}

header nav {
    text-align: center;
    padding: 0 1rem;
}

header nav a {
    color: var(--text-color);
    text-decoration: none;
    margin: 0 1rem;
    font-weight: 500;
    transition: color 0.3s;
}

header nav a:hover {
    color: var(--primary-color);
}

/* メインコンテンツ */
main {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.content-page {
    background: var(--white);
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    padding: 2rem;
}

article h1 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-color);
    line-height: 1.3;
}

article h2 {
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
    color: var(--text-color);
}

article h3 {
    font-size: 1.2rem;
    margin: 1.5rem 0 0.5rem;
    color: var(--text-color);
}

article p {
    margin-bottom: 1rem;
    text-align: justify;
}

article ul, article ol {
    margin: 1rem 0 1rem 2rem;
}

article li {
    margin-bottom: 0.5rem;
}

article a {
    color: var(--link-color);
    text-decoration: none;
}

article a:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

/* 日付と更新情報 */
.post-date, .last-updated {
    color: #666;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

/* セクション */
section {
    margin: 2rem 0;
}

/* フォーム */
.contact-form {
    margin: 2rem 0;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
}

.form-group textarea {
    resize: vertical;
}

.required {
    color: #dc2626;
}

.submit-btn {
    background: var(--primary-color);
    color: var(--white);
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.3s;
}

.submit-btn:hover {
    background: #357abd;
}

/* フッター */
footer {
    background: var(--text-color);
    color: var(--white);
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer-links {
    margin-bottom: 1rem;
}

.footer-links a {
    color: var(--white);
    text-decoration: none;
    margin: 0 1rem;
}

.footer-links a:hover {
    text-decoration: underline;
}

/* ブログインデックス */
.blog-index {
    max-width: 1000px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.blog-card {
    background: var(--white);
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    padding: 1.5rem;
    transition: transform 0.3s, box-shadow 0.3s;
}

.blog-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}

.blog-card h3 {
    margin-bottom: 0.5rem;
}

.blog-card h3 a {
    color: var(--text-color);
    text-decoration: none;
}

.blog-card h3 a:hover {
    color: var(--primary-color);
}

.blog-card p {
    color: #666;
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
}

.blog-card .read-more {
    color: var(--link-color);
    text-decoration: none;
    font-weight: 500;
}

/* レスポンシブ */
@media (max-width: 768px) {
    header nav a {
        margin: 0 0.5rem;
        font-size: 0.9rem;
    }
    
    .content-page {
        padding: 1.5rem;
    }
    
    article h1 {
        font-size: 1.5rem;
    }
    
    .blog-grid {
        grid-template-columns: 1fr;
    }
}