/* CSS Custom Properties */
:root {
    --color-primary: #6366f1;
    --color-primary-dark: #4f46e5;
    --color-secondary: #8b5cf6;
    --color-bg: #ffffff;
    --color-bg-secondary: #f9fafb;
    --color-text: #111827;
    --color-text-secondary: #6b7280;
    --color-border: #e5e7eb;
    --color-shadow: rgba(0, 0, 0, 0.1);

    /* Category colors */
    --color-announcement: #3b82f6;
    --color-changelog: #10b981;
    --color-engineering: #8b5cf6;
    --color-research: #f59e0b;
    --color-tutorial: #14b8a6;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 var(--color-shadow);
    --shadow-md: 0 4px 6px -1px var(--color-shadow);
    --shadow-lg: 0 10px 15px -3px var(--color-shadow);
}

/* Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

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

a:hover {
    text-decoration: underline;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Header */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: var(--spacing-lg) 0;
    box-shadow: var(--shadow-md);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.logo {
    font-size: 1.75rem;
    font-weight: 700;
    margin: 0;
}

.logo a {
    color: white;
    text-decoration: none;
}

.nav {
    display: flex;
    gap: var(--spacing-lg);
}

.nav-link {
    color: rgba(255, 255, 255, 0.9);
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 0.375rem;
    transition: all 0.2s;
}

.nav-link:hover {
    background-color: rgba(255, 255, 255, 0.1);
    color: white;
    text-decoration: none;
}

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

/* Main Content */
.main-content {
    padding: var(--spacing-2xl) 0;
}

/* Hero Section */
.hero {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
    padding: var(--spacing-2xl) var(--spacing-md);
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    border-radius: 0.5rem;
}

.hero h2 {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.hero p {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
}

/* Page Header */
.page-header {
    margin-bottom: var(--spacing-2xl);
}

.page-header h2 {
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.page-header p {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
}

/* MCP Section */
.mcp-section {
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-xl);
    border-radius: 0.5rem;
    margin-bottom: var(--spacing-2xl);
}

.mcp-section h2 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.mcp-section h3 {
    font-size: 1.25rem;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.mcp-content {
    line-height: 1.8;
}

.code-block {
    background-color: #1e293b;
    color: #e2e8f0;
    padding: var(--spacing-md);
    border-radius: 0.375rem;
    margin: var(--spacing-md) 0;
    overflow-x: auto;
}

.code-block pre {
    margin: 0;
}

.code-block code {
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
}

.mcp-examples {
    list-style: none;
    padding: 0;
}

.mcp-examples li {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--color-border);
}

.mcp-examples li:last-child {
    border-bottom: none;
}

.mcp-note {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background-color: #dbeafe;
    border-left: 4px solid var(--color-announcement);
    border-radius: 0.25rem;
    font-size: 0.875rem;
}

/* Site Section */
.site-section {
    margin-bottom: var(--spacing-2xl);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.section-header h2 {
    font-size: 1.5rem;
    color: var(--color-text);
}

.more-link {
    font-weight: 500;
    color: var(--color-primary);
}

/* Filters */
.filters {
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-lg);
    border-radius: 0.5rem;
    margin-bottom: var(--spacing-xl);
}

.filter-group {
    margin-bottom: var(--spacing-lg);
}

.filter-group:last-child {
    margin-bottom: 0;
}

.filter-group label {
    display: block;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.filter-buttons {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.filter-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    background-color: white;
    border-radius: 0.375rem;
    cursor: pointer;
    font-size: 0.875rem;
    transition: all 0.2s;
}

.filter-btn:hover {
    background-color: var(--color-bg-secondary);
}

.filter-btn.active {
    background-color: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

#importance-slider {
    width: 100%;
    max-width: 300px;
}

.tag-filter {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

/* Card Grid */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

/* Article Card */
.article-card {
    background-color: white;
    border: 1px solid var(--color-border);
    border-radius: 0.5rem;
    padding: var(--spacing-lg);
    transition: all 0.2s;
    box-shadow: var(--shadow-sm);
}

.article-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.article-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-md);
}

.article-meta {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    align-items: center;
}

.category-badge {
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 0.25rem;
    font-size: 0.75rem;
    font-weight: 600;
    color: white;
}

.category-announcement {
    background-color: var(--color-announcement);
}

.category-changelog {
    background-color: var(--color-changelog);
}

.category-engineering {
    background-color: var(--color-engineering);
}

.category-research {
    background-color: var(--color-research);
}

.category-tutorial {
    background-color: var(--color-tutorial);
}

.new-badge {
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: #ef4444;
    color: white;
    border-radius: 0.25rem;
    font-size: 0.75rem;
    font-weight: 700;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.7;
    }
}

.importance-stars {
    color: #fbbf24;
    font-size: 0.875rem;
}

.article-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.article-title a {
    color: var(--color-text);
}

.article-title a:hover {
    color: var(--color-primary);
}

.article-summary {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.article-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border);
}

.article-tags {
    display: flex;
    gap: var(--spacing-xs);
    flex-wrap: wrap;
}

.tag {
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-bg-secondary);
    border-radius: 0.25rem;
    font-size: 0.75rem;
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all 0.2s;
}

.tag:hover {
    background-color: var(--color-primary);
    color: white;
}

.tag.active {
    background-color: var(--color-primary);
    color: white;
}

.article-date {
    font-size: 0.75rem;
    color: var(--color-text-secondary);
}

.share-buttons {
    display: flex;
    gap: var(--spacing-sm);
}

.share-btn {
    padding: var(--spacing-xs) var(--spacing-sm);
    border: 1px solid var(--color-border);
    background-color: white;
    border-radius: 0.25rem;
    cursor: pointer;
    font-size: 0.75rem;
    transition: all 0.2s;
}

.share-btn:hover {
    background-color: var(--color-bg-secondary);
}

/* Timeline */
.timeline-section {
    margin-top: var(--spacing-2xl);
}

.timeline-section h2 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.timeline {
    background-color: white;
    border: 1px solid var(--color-border);
    border-radius: 0.5rem;
    padding: var(--spacing-lg);
}

.timeline-item {
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--color-border);
}

.timeline-item:last-child {
    border-bottom: none;
}

.timeline-item:hover {
    background-color: var(--color-bg-secondary);
}

.timeline-date {
    font-size: 0.75rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
}

.timeline-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
}

.timeline-title {
    font-weight: 600;
    color: var(--color-text);
    flex: 1;
}

.timeline-title a {
    color: var(--color-text);
}

.timeline-title a:hover {
    color: var(--color-primary);
}

.timeline-site {
    font-size: 0.75rem;
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-bg-secondary);
    border-radius: 0.25rem;
    color: var(--color-text-secondary);
}

/* No Results */
.no-results {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--color-text-secondary);
}

/* Footer */
.footer {
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-xl) 0;
    margin-top: var(--spacing-2xl);
    border-top: 1px solid var(--color-border);
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.footer p {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
}

.footer-links {
    display: flex;
    gap: var(--spacing-lg);
}

.footer-links a {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
}

.footer-links a:hover {
    color: var(--color-primary);
}

/* Responsive Design */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        align-items: flex-start;
    }

    .nav {
        flex-wrap: wrap;
    }

    .hero h2 {
        font-size: 1.5rem;
    }

    .page-header h2 {
        font-size: 1.5rem;
    }

    .card-grid {
        grid-template-columns: 1fr;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }

    .hero {
        padding: var(--spacing-lg) var(--spacing-sm);
    }

    .hero h2 {
        font-size: 1.25rem;
    }

    .mcp-section {
        padding: var(--spacing-md);
    }

    .filters {
        padding: var(--spacing-md);
    }

    .filter-buttons {
        gap: var(--spacing-xs);
    }

    .filter-btn {
        font-size: 0.75rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }

    .article-card {
        padding: var(--spacing-md);
    }
}