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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: #333;
    font-weight: bold;
    font-size: 1.2rem;
}

.logo {
    width: 40px;
    height: 40px;
    margin-right: 10px;
}

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

.nav-link {
    text-decoration: none;
    color: #666;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
    color: #007bff;
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
}

/* Main */
.main {
    margin-top: 70px;
    min-height: calc(100vh - 70px);
}

/* Hero */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 80px 20px;
    display: flex;
    align-items: center;
    min-height: 500px;
}

.hero-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: bold;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.cta-button {
    display: inline-block;
    background: #fff;
    color: #667eea;
    padding: 15px 30px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: bold;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}

.hero-bg {
    width: 100%;
    height: auto;
    max-width: 400px;
}

/* Sections */
.featured-section,
.categories-section {
    padding: 80px 20px;
}

.categories-section {
    background: #f8f9fa;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: #333;
}

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

.video-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-decoration: none;
    color: inherit;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.video-thumbnail {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.video-info {
    padding: 1.5rem;
}

.video-title {
    font-size: 1.2rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
    line-height: 1.3;
}

.video-channel {
    color: #666;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.video-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    color: #999;
    margin-bottom: 1rem;
}

.video-description {
    font-size: 0.9rem;
    color: #666;
    line-height: 1.4;
}

.video-category {
    display: inline-block;
    background: #e3f2fd;
    color: #1976d2;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    margin-bottom: 1rem;
}

/* Category Grid */
.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.category-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
    text-decoration: none;
    color: inherit;
}

.category-card:hover {
    transform: translateY(-3px);
}

.category-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.category-name {
    font-size: 1.3rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.category-count {
    color: #666;
    font-size: 0.9rem;
}

/* Buttons */
.view-all-button {
    display: inline-block;
    background: #007bff;
    color: white;
    padding: 12px 30px;
    border-radius: 25px;
    text-decoration: none;
    font-weight: 500;
    transition: background-color 0.3s ease;
}

.view-all-button:hover {
    background: #0056b3;
}

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

/* Search and Filter */
.search-section {
    background: #f8f9fa;
    padding: 2rem 0;
}

.search-container {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.search-input {
    flex: 1;
    min-width: 300px;
    padding: 12px 16px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
}

.search-input:focus {
    outline: none;
    border-color: #007bff;
}

.filter-select {
    padding: 12px 16px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
    background: white;
}

.search-button {
    padding: 12px 24px;
    background: #007bff;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.search-button:hover {
    background: #0056b3;
}

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

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

.video-embed {
    width: 100%;
    height: 400px;
    border: none;
    border-radius: 8px;
}

.video-detail-info h1 {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.video-detail-meta {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.video-detail-description {
    line-height: 1.6;
    margin-bottom: 2rem;
}

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

.topic-tag {
    display: inline-block;
    background: #e9ecef;
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.9rem;
    margin: 0 8px 8px 0;
}

.content-notice {
    background: #f8f9fa;
    padding: 1rem;
    border-left: 4px solid #007bff;
    margin-bottom: 2rem;
    border-radius: 0 4px 4px 0;
}

/* Footer */
.footer {
    background: #333;
    color: white;
    padding: 3rem 0 1rem;
}

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

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
}

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

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

.footer-section a {
    color: #ccc;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #555;
    color: #ccc;
}

/* Page Specific */
.page-header {
    background: #f8f9fa;
    padding: 2rem 0;
    margin-bottom: 2rem;
}

.page-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 1rem;
}

.page-subtitle {
    text-align: center;
    color: #666;
    font-size: 1.1rem;
}

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

.content-section h2 {
    margin-bottom: 1.5rem;
    color: #333;
}

.content-section p {
    margin-bottom: 1rem;
    line-height: 1.6;
}

.content-section ul {
    margin-bottom: 1rem;
    padding-left: 2rem;
}

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

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

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

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

.form-input,
.form-textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: #007bff;
}

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

.form-button {
    background: #007bff;
    color: white;
    padding: 12px 30px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.form-button:hover {
    background: #0056b3;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 1rem;
        box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    }

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

    .nav-toggle {
        display: block;
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

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

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

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

    .search-input {
        min-width: auto;
    }

    .video-detail-meta {
        flex-direction: column;
        gap: 1rem;
    }

    .video-embed {
        height: 250px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 40px 20px;
    }

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

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

    .featured-section,
    .categories-section {
        padding: 40px 20px;
    }
}