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

:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #64748b;
    --background: #ffffff;
    --surface: #f8fafc;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius: 8px;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
.header {
    background: var(--background);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.125rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    gap: 4px;
}

.nav-toggle span {
    width: 20px;
    height: 2px;
    background: var(--text-primary);
    transition: 0.3s;
}

/* Main */
.main {
    min-height: calc(100vh - 64px);
}

/* Hero */
.hero {
    padding: 4rem 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 500px;
    background: linear-gradient(135deg, var(--surface) 0%, var(--background) 100%);
}

.hero-content {
    max-width: 1200px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    width: 100%;
}

.hero-content h1 {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.hero-content p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.hero-bg {
    display: flex;
    justify-content: center;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s;
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

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

/* Sections */
.featured,
.categories-preview {
    padding: 4rem 0;
}

.featured h2,
.categories-preview h2 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 2rem;
    text-align: center;
}

/* Video Grid */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.video-card {
    background: var(--background);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: transform 0.2s, box-shadow 0.2s;
    text-decoration: none;
    color: inherit;
}

.video-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.video-thumbnail {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--surface);
}

.video-info {
    padding: 1.5rem;
}

.video-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

.video-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.video-description {
    color: var(--text-secondary);
    font-size: 0.875rem;
    line-height: 1.5;
}

/* Category Grid */
.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.category-card {
    background: var(--background);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    text-decoration: none;
    color: inherit;
    transition: transform 0.2s, box-shadow 0.2s;
    text-align: center;
}

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

.category-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

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

/* Section Footer */
.section-footer {
    text-align: center;
}

/* Video Detail */
.video-detail {
    padding: 2rem 0;
}

.video-player {
    margin-bottom: 2rem;
}

.video-embed {
    width: 100%;
    height: 500px;
    border: none;
    border-radius: var(--radius);
}

.video-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
}

.video-main h1 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.video-main .video-meta {
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border);
}

.video-sidebar {
    background: var(--surface);
    padding: 2rem;
    border-radius: var(--radius);
    height: fit-content;
}

.video-sidebar h3 {
    margin-bottom: 1rem;
}

.video-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

.tag {
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
}

/* Search and Filters */
.search-filters {
    padding: 2rem 0;
    background: var(--surface);
    margin-bottom: 2rem;
}

.search-bar {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.search-input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
}

.filters {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.filter-select {
    padding: 0.5rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--background);
}

/* Footer */
.footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 3rem 0 1rem;
    margin-top: 4rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
}

/* Contact Form */
.contact-form {
    max-width: 600px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
}

.form-group textarea {
    height: 120px;
    resize: vertical;
}

/* Page Content */
.page-content {
    padding: 3rem 0;
}

.page-content h1 {
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    text-align: center;
}

.page-content h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 2rem 0 1rem;
}

.page-content p {
    margin-bottom: 1rem;
    line-height: 1.7;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-content h1 {
        font-size: 2rem;
    }
    
    .video-grid {
        grid-template-columns: 1fr;
    }
    
    .video-content {
        grid-template-columns: 1fr;
    }
    
    .video-embed {
        height: 300px;
    }
    
    .search-bar {
        flex-direction: column;
    }
    
    .filters {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.5rem;
    }
    
    .hero {
        padding: 2rem 1rem;
    }
    
    .featured,
    .categories-preview {
        padding: 2rem 0;
    }
    
    .video-info {
        padding: 1rem;
    }
    
    .category-card {
        padding: 1.5rem;
    }
}

/* RTL Support */
[dir="rtl"] {
    text-align: right;
}

[dir="rtl"] .nav-container {
    flex-direction: row-reverse;
}

[dir="rtl"] .nav-menu {
    flex-direction: row-reverse;
}

[dir="rtl"] .hero-content {
    text-align: right;
}

[dir="rtl"] .video-meta {
    flex-direction: row-reverse;
}