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

:root {
    --primary-color: hsl(175, 70%, 50%);
    --primary-dark: hsl(175, 70%, 40%);
    --secondary-color: hsl(220, 15%, 25%);
    --accent-color: hsl(45, 100%, 60%);
    --text-color: hsl(220, 15%, 20%);
    --text-light: hsl(220, 10%, 50%);
    --bg-color: hsl(0, 0%, 98%);
    --bg-secondary: hsl(0, 0%, 95%);
    --border-color: hsl(220, 15%, 90%);
    --shadow: 0 2px 10px hsla(220, 15%, 20%, 0.1);
    --shadow-hover: 0 4px 20px hsla(220, 15%, 20%, 0.15);
    --border-radius: 8px;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --max-width: 1200px;
    --header-height: 70px;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: white;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-height);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-color);
    font-weight: 700;
    font-size: 1.2rem;
}

.logo {
    width: 40px;
    height: 40px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    padding: 8px 16px;
    border-radius: var(--border-radius);
    transition: all 0.2s ease;
}

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

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
}

/* Main Content */
.main {
    flex: 1;
    padding-top: 0;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    padding: 80px 20px;
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.2rem;
    margin-bottom: 40px;
    opacity: 0.9;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-actions {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    text-align: center;
    transition: all 0.2s ease;
    border: 2px solid transparent;
    cursor: pointer;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: transparent;
    color: white;
    border-color: white;
}

.btn-secondary {
    background-color: transparent;
    color: white;
    border-color: white;
}

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

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

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

.btn-small {
    padding: 8px 16px;
    font-size: 0.9rem;
}

/* Sections */
.featured,
.categories-preview {
    padding: 60px 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 50px;
    color: var(--text-color);
}

.section-footer {
    text-align: center;
    margin-top: 40px;
}

/* Video Grid */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.video-card {
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.video-thumbnail {
    position: relative;
    aspect-ratio: 16/9;
    overflow: hidden;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.video-card:hover .video-thumbnail img {
    transform: scale(1.05);
}

.video-duration {
    position: absolute;
    bottom: 8px;
    right: 8px;
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 600;
}

.video-info {
    padding: 20px;
}

.video-title {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-color);
    line-height: 1.3;
}

.video-channel {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 12px;
}

.video-meta {
    display: flex;
    gap: 15px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}

.video-category {
    background: var(--primary-color);
    color: white;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 600;
}

.video-views {
    color: var(--text-light);
    font-size: 0.8rem;
}

.video-description {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 15px;
    line-height: 1.4;
}

/* Category Grid */
.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.category-card {
    background: white;
    padding: 30px;
    border-radius: var(--border-radius);
    text-align: center;
    text-decoration: none;
    color: var(--text-color);
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.category-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-color);
}

.category-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.category-card p {
    color: var(--text-light);
    margin-bottom: 15px;
}

.category-count {
    display: inline-block;
    background: var(--bg-secondary);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-color);
}

/* Search and Filter */
.search-section {
    background: var(--bg-secondary);
    padding: 30px 0;
}

.search-container {
    max-width: 800px;
    margin: 0 auto;
}

.search-form {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.search-input {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    min-width: 250px;
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.filter-select {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    background: white;
    min-width: 150px;
}

.filter-select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.search-results {
    text-align: center;
    color: var(--text-light);
    font-size: 0.9rem;
}

/* Video Detail */
.video-detail {
    padding: 40px 0;
}

.video-player {
    aspect-ratio: 16/9;
    width: 100%;
    max-width: 800px;
    margin: 0 auto 30px;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}

.video-embed {
    width: 100%;
    height: 100%;
    border: none;
}

.video-details {
    max-width: 800px;
    margin: 0 auto;
}

.video-header {
    margin-bottom: 20px;
}

.video-header h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--text-color);
}

.video-metadata {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
    flex-wrap: wrap;
    align-items: center;
}

.video-topics {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin: 20px 0;
}

.topic-tag {
    background: var(--bg-secondary);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

.content-notice {
    background: var(--bg-secondary);
    padding: 15px;
    border-radius: var(--border-radius);
    margin-top: 20px;
    font-size: 0.9rem;
    color: var(--text-light);
    border-left: 4px solid var(--primary-color);
}

/* Footer */
.footer {
    background: var(--secondary-color);
    color: white;
    padding: 50px 0 20px;
    margin-top: auto;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 30px;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 15px;
    color: var(--primary-color);
}

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

.footer-section ul li {
    margin-bottom: 8px;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 20px;
    text-align: center;
    color: rgba(255, 255, 255, 0.7);
}

.disclaimer-text {
    margin-top: 10px;
    font-size: 0.9rem;
}

/* Page Specific */
.page-header {
    background: var(--bg-secondary);
    padding: 40px 0;
    text-align: center;
}

.page-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 10px;
}

.page-subtitle {
    color: var(--text-light);
    font-size: 1.1rem;
}

.page-content {
    padding: 40px 0;
}

.content-section {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.content-section h2 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 1.5rem;
}

.content-section h3 {
    color: var(--text-color);
    margin: 20px 0 10px;
}

.content-section p {
    margin-bottom: 15px;
    line-height: 1.6;
}

.content-section ul {
    margin: 15px 0;
    padding-left: 30px;
}

.content-section li {
    margin-bottom: 8px;
}

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

.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-color);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.2s ease;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow);
        gap: 10px;
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-toggle {
        display: block;
    }

    .hero-title {
        font-size: 2.2rem;
    }

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .hero-actions {
        flex-direction: column;
        align-items: center;
    }

    .video-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

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

    .search-form {
        flex-direction: column;
    }

    .search-input,
    .filter-select {
        min-width: auto;
    }

    .video-metadata {
        flex-direction: column;
        gap: 10px;
        align-items: flex-start;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .content-section {
        padding: 30px 20px;
    }

    .container {
        padding: 0 15px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 60px 20px;
    }

    .hero-title {
        font-size: 1.8rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .page-title {
        font-size: 2rem;
    }

    .video-card {
        margin: 0;
    }

    .video-info {
        padding: 15px;
    }

    .category-card {
        padding: 20px;
    }
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.text-left {
    text-align: left;
}

.text-right {
    text-align: right;
}

.mt-1 { margin-top: 10px; }
.mt-2 { margin-top: 20px; }
.mt-3 { margin-top: 30px; }
.mb-1 { margin-bottom: 10px; }
.mb-2 { margin-bottom: 20px; }
.mb-3 { margin-bottom: 30px; }