/* 基本設定 */
body {
    margin: 0;
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", sans-serif;
    background-color: #f8f9fa;
    color: #333;
    line-height: 1.8;
}

/* ヘッダー */
.main-header {
    background: #fff;
    padding: 20px;
    border-bottom: 2px solid #003366;
    text-align: center;
}

.main-header h1 {
    margin: 0;
    font-size: 1.5rem;
    color: #003366;
}

/* レイアウト構成 */
.container {
    display: flex; /* Flexboxで横並び */
    max-width: 1200px;
    margin: 20px auto;
    gap: 30px;
    padding: 0 20px;
}

/* サイドバー */
.sidebar {
    flex: 0 0 250px;
    background: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    height: fit-content;
}

.sidebar h2 {
    font-size: 1.1rem;
    background: #003366;
    color: #fff;
    padding: 10px;
    margin: -20px -20px 20px -20px;
    border-radius: 8px 8px 0 0;
}

.sidebar ul {
    list-style: none;
    padding: 0;
}

.sidebar li {
    margin-bottom: 10px;
    border-bottom: 1px solid #eee;
}

.sidebar a {
    text-decoration: none;
    color: #444;
    font-size: 0.9rem;
    display: block;
    padding: 8px 0;
    transition: 0.3s;
}

.sidebar a:hover {
    color: #007bff;
    padding-left: 5px;
}

/* メインコンテンツ */
.content {
    flex: 1;
    background: #fff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.hero-image img {
    width: 100%;
    height: auto;
    border-radius: 5px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

/* 特徴のグリッドレイアウト */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.feature-item {
    background: #eef2f7;
    padding: 15px;
    border-radius: 5px;
}

.feature-item h4 {
    margin: 0 0 10px 0;
    color: #003366;
}

/* スマホ対応 */
@media (max-width: 768px) {
    .container {
        flex-direction: column;
    }
    .sidebar {
        flex: none;
        order: 2;
    }
    .content {
        order: 1;
    }
}