body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}

header {
    background-color: #002f5f;
    color: white;
    padding: 10px 0;
    text-align: center;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 10px;
}

.logo {
    max-width: 200px; /* 小さめに調整 */
    height: auto;
}

.nav-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 20px;
    margin-top: 10px;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: bold;
}

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

.filter-section {
    background-color: #fff;
    padding: 10px;
    text-align: center;
    border-bottom: 1px solid #ccc;
}

.filter-section button {
    margin: 5px;
    padding: 8px 16px;
    cursor: pointer;
    border: 1px solid #ccc;
    border-radius: 4px;
    background-color: #f0f0f0;
}

.category-filter,
.tag-filter {
    margin: 10px 0;
}

.category-filter button,
.tag-filter button {
    margin: 4px;
    padding: 6px 14px;
    font-size: 0.95em;
    border: 1px solid #aaa;
    border-radius: 4px;
    background-color: #eee;
    cursor: pointer;
}

/* active class for filters */
.category-filter button.active,
.tag-filter button.active {
    background-color: #007bff;
    color: white;
    font-weight: bold;
}

.content-container {
    display: flex;
    flex-direction: row;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    gap: 20px;
}

.news-list {
    flex: 3;
}

.sidebar {
    flex: 1;
    background-color: #fafafa;
    padding: 10px;
    border-left: 1px solid #ccc;
}

.sidebar h3 {
    margin-top: 0;
}

.news-item {
    background-color: white;
    padding: 10px;
    margin-bottom: 10px;
    border-radius: 5px;
    box-shadow: 0 0 5px rgba(0,0,0,0.1);
}

.news-item img {
    max-width: 100%;
    height: auto;
    display: block;
    margin-bottom: 10px;
}

footer {
    text-align: center;
    padding: 20px;
    background-color: #002f5f;
    color: white;
    margin-top: 20px;
}

@media screen and (max-width: 768px) {
    .content-container {
        flex-direction: column;
    }
    .nav-links {
        flex-direction: column;
        gap: 10px;
    }
    .logo {
        max-width: 60%;
    }
}

/* ダークモード対応 */
@media (prefers-color-scheme: dark) {
    body {
        background-color: #111;
        color: #eee;
    }
    .news-item {
        background-color: #222;
    }
    .sidebar {
        background-color: #1a1a1a;
        color: #eee;
    }
    .filter-section {
        background-color: #1a1a1a;
    }
    footer {
        background-color: #000;
    }
    .nav-links a {
        color: #ddd;
    }

    .category-filter button,
    .tag-filter button {
        background-color: #333;
        border-color: #666;
        color: #ddd;
    }

    .category-filter button.active,
    .tag-filter button.active {
        background-color: #0d6efd;
        color: #fff;
    }
}