:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --text-color: #1f2937;
    --light-bg: #f3f4f6;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
.selected-menu{
    color: #fdfdfd;
    font-weight: bold;
    background-color: #002597;
    padding: 0 10px;
    border-radius: 10px;
}

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

.header {
    background-color: white;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s;
}

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

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

.page-header {
    padding: 8rem 2rem 4rem;
    background: linear-gradient(123deg, #002597 10%, #183e31 57%);
    color: white;
    text-align: center;
}

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

.page-description {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.2rem;
}

.filter-section {
    background: white;
    padding: 1rem 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.filter-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 0.5rem 1rem;
    border: 2px solid var(--primary-color);
    border-radius: 0.5rem;
    background: none;
    color: var(--primary-color);
    cursor: pointer;
    transition: all 0.3s;
}

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

.videos-container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 2rem;
}

.videos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.video-card {
    background: white;
    border-radius: 0.5rem;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

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

.video-container {
    position: relative;
    width: 100%;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
    overflow: hidden;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

.video-info {
    padding: 1.5rem;
}

.video-category {
    font-size: 0.875rem;
    color: var(--primary-color);
    text-transform: uppercase;
    margin-bottom: 0.5rem;
}

.video-title {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
    font-weight: bold;
}

.video-description {
    color: #666;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-metadata {
    display: flex;
    align-items: center;
    gap: 1rem;
    font-size: 0.875rem;
    color: #666;
}

.video-metadata i {
    font-size: 1rem;
}

.footer {
    background: linear-gradient(123deg, #002597 10%, #183e31 57%);
    color: white;
    padding: 3rem 2rem;
    text-align: center;
    margin-top: 4rem;
}

.social-links {
    margin-top: 1.5rem;
}

.social-links a {
    color: white;
    font-size: 1.5rem;
    margin: 0 0.5rem;
    transition: color 0.3s;
}

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

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        padding: 1rem;
        flex-direction: column;
        gap: 1rem;
        box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    }

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

    .mobile-menu-btn {
        display: block;
    }

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

    .filter-container {
        justify-content: center;
    }
}