:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --light-color: #ecf0f1;
    --dark-color: #34495e;
}

.useful-links-container {
    display: flex;
    min-height: 100vh;
    gap: 0;
    font-family: 'Noto Sans KR', sans-serif;
    background: var(--light-color);
}

.useful-links-sidebar {
    width: 240px;
    flex-shrink: 0;
    background: #fff;
    padding: 28px 18px 24px 18px;
    border-right: 1px solid #e9ecef;
    box-shadow: 0 2px 8px rgba(44,62,80,0.04);
}

.useful-links-main {
    flex: 1;
    padding: 32px 32px 32px 32px;
    overflow-y: auto;
    background: var(--light-color);
}

.useful-links-menu {
    list-style: none;
    padding: 0;
    margin: 0;
}

.useful-links-menu li {
    margin-bottom: 5px;
}

.useful-links-menu a {
    display: block;
    padding: 10px 15px;
    text-decoration: none;
    color: var(--primary-color);
    border-radius: 8px;
    font-weight: 500;
    transition: background 0.3s, color 0.3s;
}

.useful-links-menu a:hover,
.useful-links-menu a.active {
    background: var(--secondary-color);
    color: #fff;
}

.sort-controls {
    margin-bottom: 24px;
    padding: 18px 20px;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(44,62,80,0.04);
    border: 1px solid #e9ecef;
}

.sort-controls label {
    margin-right: 10px;
    font-weight: bold;
}

.sort-controls select,
.sort-controls input {
    padding: 5px 10px;
    border: 1px solid #ccc;
    border-radius: 3px;
}

.tag-filter-container {
    margin-top: 10px;
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    align-items: center;
}

.tag-filter-label {
    font-weight: bold;
    margin-right: 10px;
}

.tag-filter {
    padding: 4px 8px;
    background: var(--light-color);
    border-radius: 3px;
    font-size: 11px;
    color: var(--dark-color);
    cursor: pointer;
    transition: background 0.3s, color 0.3s;
}

.tag-filter.active {
    background: var(--secondary-color);
    color: #fff;
}

.category-section {
    margin-bottom: 30px;
}

.category-section h3 {
    margin-bottom: 18px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--secondary-color);
    color: var(--primary-color);
    font-size: 1.25rem;
    font-weight: 700;
}

.site-item {
    margin-bottom: 24px;
    padding: 20px 22px;
    border: 1px solid #e9ecef;
    border-radius: 12px;
    background: #fff;
    box-shadow: 0 2px 8px rgba(44,62,80,0.04);
}

.site-item h4 {
    margin: 0 0 10px 0;
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    font-size: 1.08rem;
    font-weight: 600;
}

.site-item h4 a {
    text-decoration: none;
    color: var(--secondary-color);
}

.site-item h4 a:hover {
    text-decoration: underline;
}

.child-items {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-top: 10px;
}

.child-item {
    flex: 0 0 300px;
    padding: 10px;
    border: 1px solid #e9ecef;
    border-radius: 8px;
    background: #fff;
}

.child-item h5 {
    margin: 0 0 5px 0;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.95rem;
    font-weight: 500;
}

.category-badge {
    padding: 3px 8px;
    border-radius: 3px;
    font-size: 12px;
    font-weight: bold;
    text-transform: uppercase;
}

.category-badge.essential {
    background: var(--accent-color);
    color: #fff;
}

.category-badge.important {
    background: #fd7e14;
    color: #fff;
}

.category-badge.reference {
    background: #6c757d;
    color: #fff;
}

.category-badge.information,
.category-badge.unknown {
    background: #adb5bd;
    color: #fff;
}

.region-badge {
    padding: 3px 8px;
    border-radius: 3px;
    font-size: 12px;
    font-weight: bold;
    border: 1px solid var(--secondary-color);
    color: var(--secondary-color);
    background: #fff;
}

.description {
    margin: 10px 0;
    color: #666;
}

.meta {
    display: flex;
    gap: 15px;
    margin: 10px 0;
    font-size: 12px;
    color: #888;
    flex-wrap: wrap;
}

.meta span {
    white-space: nowrap;
}

.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    margin-top: 10px;
}

.tag {
    padding: 2px 6px;
    background: var(--light-color);
    border-radius: 3px;
    font-size: 11px;
    color: var(--dark-color);
}

.pagination-controls button {
    padding: 5px 10px;
    margin: 0 5px;
    border: 1px solid var(--secondary-color);
    background: #fff;
    color: var(--secondary-color);
    border-radius: 3px;
    cursor: pointer;
    transition: background 0.3s, color 0.3s;
}

.pagination-controls button:hover:not(:disabled) {
    background: var(--secondary-color);
    color: #fff;
}

.pagination-controls button:disabled {
    color: #ccc;
    border-color: #ccc;
    cursor: not-allowed;
}

.pagination-controls .page-number {
    padding: 5px 10px;
    margin: 0 5px;
    border: 1px solid var(--secondary-color);
    border-radius: 3px;
    cursor: pointer;
    transition: background 0.3s, color 0.3s;
}

.pagination-controls .page-number.active {
    background: var(--secondary-color);
    color: #fff;
    cursor: default;
}

.pagination-controls .page-number:hover:not(.active) {
    background: var(--secondary-color);
    color: #fff;
}

.loading {
    text-align: center;
    padding: 50px;
    color: #666;
    font-size: 1.1rem;
}

.error {
    color: var(--accent-color);
    text-align: center;
    padding: 20px;
    font-size: 1.1rem;
}

@media (max-width: 768px) {
    .useful-links-container {
        flex-direction: column;
    }
    
    .useful-links-sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid #dee2e6;
    }
    
    .useful-links-menu {
        display: flex;
        flex-wrap: wrap;
        gap: 10px;
    }
    
    .site-item h4,
    .child-item h5 {
        flex-direction: column;
        align-items: flex-start;
        gap: 5px;
    }
    
    .meta {
        flex-direction: column;
        gap: 5px;
    }
    
    .child-items {
        flex-direction: column;
    }
    
    .child-item {
        flex: 1;
    }
}