:root {
    --primary-color: #4a90d9;
    --secondary-color: #6c5ce7;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-color: #333;
    --text-secondary: #666;
    --border-color: #e1e8ef;
    --shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    --radius: 12px;
    --transition: all 0.3s ease;
}

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

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

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
}

.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1rem 0;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.search-box {
    display: flex;
    gap: 0.5rem;
    flex: 1;
    max-width: 500px;
}

.search-box input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: none;
    border-radius: 25px;
    font-size: 1rem;
    outline: none;
    transition: var(--transition);
}

.search-box input:focus {
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.3);
}

.search-box button {
    padding: 0.75rem 1.5rem;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 25px;
    color: white;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.search-box button:hover {
    background: rgba(255, 255, 255, 0.3);
}

.user-nav {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.nav-link {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    transition: var(--transition);
    font-weight: 500;
}

.nav-link:hover, .nav-link.active {
    background: rgba(255, 255, 255, 0.2);
}

.main-content {
    padding: 2rem 0;
}

.main-content .container {
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: 2rem;
}

.sidebar {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    height: fit-content;
    position: sticky;
    top: 100px;
}

.sidebar-section h3 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--text-color);
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-color);
}

.category-list {
    list-style: none;
}

.category-list li {
    margin-bottom: 0.5rem;
}

.category-list a {
    display: block;
    padding: 0.75rem 1rem;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 8px;
    transition: var(--transition);
    font-size: 0.95rem;
}

.category-list a:hover {
    background: var(--bg-color);
    color: var(--primary-color);
}

.category-list a.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    font-weight: 600;
}

.content {
    min-height: 500px;
}

.search-results {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.search-results h2 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.category-section {
    margin-bottom: 2.5rem;
}

.category-title {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.category-title::before {
    content: '';
    width: 4px;
    height: 24px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

.sites-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 1.5rem;
}

.site-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    position: relative;
    border: 1px solid var(--border-color);
}

.site-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.12);
    border-color: var(--primary-color);
}

.site-link {
    text-decoration: none;
    color: inherit;
    display: block;
}

.site-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    object-fit: contain;
    margin-bottom: 1rem;
}

.site-icon-placeholder {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.site-title {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.site-description {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.favorite-btn {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    padding: 0.25rem;
    transition: var(--transition);
    opacity: 0;
}

.site-card:hover .favorite-btn {
    opacity: 1;
}

.favorite-btn:hover {
    transform: scale(1.2);
}

.favorite-btn.favorited {
    opacity: 1;
}

.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-secondary);
}

.empty-state p {
    font-size: 1.1rem;
}

.footer {
    background: var(--card-bg);
    padding: 2rem 0;
    text-align: center;
    margin-top: 3rem;
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.05);
}

.footer p {
    color: var(--text-secondary);
}

.alert {
    position: fixed;
    top: 80px;
    right: 20px;
    padding: 1rem 1.5rem;
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    z-index: 1000;
    animation: slideIn 0.3s ease;
}

.alert.success {
    border-left: 4px solid #10b981;
}

.alert.error {
    border-left: 4px solid #ef4444;
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@media (max-width: 900px) {
    .main-content .container {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
    }

    .header-content {
        flex-direction: column;
    }

    .search-box {
        width: 100%;
    }

    .sites-grid {
        grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    }
}

@media (max-width: 600px) {
    .logo {
        font-size: 1.4rem;
    }

    .sites-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
    }

    .site-card {
        padding: 1rem;
    }

    .site-icon, .site-icon-placeholder {
        width: 40px;
        height: 40px;
    }
}