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

        :root {
            --primary-color: #2563eb;
            --primary-light: #60a5fa;
            --primary-dark: #1e40af;
            --secondary-color: #1e293b;
            --text-primary: #1e293b;
            --text-secondary: #64748b;
            --bg-light: #f8fafc;
            --bg-white: #ffffff;
            --bg-card: #ffffff;
            --bg-hover: #f1f5f9;
            --border-color: #e2e8f0;
            --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
            --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
            --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
            --shadow-xl: 0 20px 40px rgba(37, 99, 235, 0.15);
            --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: linear-gradient(135deg, #f8fafc 0%, #e0f2fe 100%);
            color: var(--text-primary);
            min-height: 100vh;
            overflow-x: hidden;
        }

        /* Gallery Container */
        .gallery-wrapper {
            max-width: 1400px;
            margin: 1rem auto 1rem auto;
            padding: 0 5%;
        }

        /* Gallery Title */
        .gallery-title {
            text-align: center;
            margin-bottom: 3rem;
        }

        .gallery-title h1 {
            font-size: 2.5rem;
            font-weight: 700;
            margin-bottom: 0.5rem;
            background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 1rem;
        }

        .gallery-title p {
            color: var(--text-secondary);
            font-size: 1.1rem;
            font-weight: 400;
        }

        /* Search and Filter Section */
        .controls {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 1.5rem;
            margin-bottom: 2rem;
            background: var(--bg-white);
            padding: 1.5rem;
            border-radius: 16px;
            box-shadow: var(--shadow-md);
        }

        .search-box {
            position: relative;
            flex: 1;
            max-width: 400px;
        }

        .search-box input {
            width: 100%;
            padding: 0.875rem 3rem 0.875rem 1.25rem;
            background: var(--bg-light);
            border: 2px solid var(--border-color);
            border-radius: 12px;
            color: var(--text-primary);
            font-size: 1rem;
            font-weight: 500;
            transition: var(--transition);
        }

        .search-box input:focus {
            outline: none;
            border-color: var(--primary-color);
            background: var(--bg-white);
            box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
        }

        .search-box input::placeholder {
            color: var(--text-secondary);
        }

        .search-box i {
            position: absolute;
            right: 1.25rem;
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-secondary);
        }

        .filter-buttons {
            display: flex;
            gap: 0.75rem;
            flex-wrap: wrap;
        }

        .filter-btn {
            padding: 0.75rem 1.5rem;
            background: var(--bg-light);
            border: 2px solid var(--border-color);
            border-radius: 10px;
            color: var(--text-secondary);
            cursor: pointer;
            transition: var(--transition);
            font-size: 0.9rem;
            font-weight: 600;
        }

        .filter-btn:hover {
            background: var(--bg-hover);
            border-color: var(--primary-light);
            color: var(--primary-color);
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
        }

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

        /* Video Gallery Grid */
        .video-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
            gap: 1.5rem;
            animation: fadeIn 0.8s ease;
        }

        .video-card {
            background: var(--bg-white);
            border-radius: 16px;
            overflow: hidden;
            transition: var(--transition);
            cursor: pointer;
            position: relative;
            animation: slideUp 0.6s ease both;
            border: 1px solid var(--border-color);
        }

        .video-card:hover {
            transform: translateY(-8px);
            box-shadow: var(--shadow-xl);
            border-color: var(--primary-light);
        }

        .video-thumbnail {
            position: relative;
            width: 100%;
            height: 200px;
            overflow: hidden;
            background: var(--bg-light);
        }

        .video-thumbnail img {
            width: 100%;
            height: 100%;
            object-fit: cover;
            transition: var(--transition);
        }

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

        .youtube-badge {
            position: absolute;
            top: 12px;
            left: 12px;
            background: #ff0000;
            color: white;
            padding: 0.375rem 0.75rem;
            border-radius: 8px;
            font-size: 0.75rem;
            font-weight: 700;
            display: flex;
            align-items: center;
            gap: 0.375rem;
            box-shadow: var(--shadow-md);
        }

        .play-overlay {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            width: 64px;
            height: 64px;
            background: rgba(37, 99, 235, 0.95);
            backdrop-filter: blur(10px);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: var(--transition);
            opacity: 0;
            box-shadow: var(--shadow-lg);
        }

        .video-card:hover .play-overlay {
            opacity: 1;
            transform: translate(-50%, -50%) scale(1.1);
        }

        .play-overlay i {
            color: white;
            font-size: 1.5rem;
            margin-left: 3px;
        }

        .video-duration {
            position: absolute;
            bottom: 12px;
            right: 12px;
            background: rgba(30, 41, 59, 0.9);
            backdrop-filter: blur(10px);
            color: white;
            padding: 0.375rem 0.625rem;
            border-radius: 6px;
            font-size: 0.8rem;
            font-weight: 600;
        }

        .video-info {
            padding: 1.25rem;
        }

        .video-title {
            font-size: 1.1rem;
            font-weight: 600;
            margin-bottom: 0.75rem;
            color: var(--text-primary);
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
            line-height: 1.4;
        }

        .video-meta {
            display: flex;
            justify-content: space-between;
            align-items: center;
            color: var(--text-secondary);
            font-size: 0.9rem;
        }

        .video-views {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            font-weight: 500;
        }

        .video-category {
            background: linear-gradient(135deg, var(--primary-light), var(--primary-color));
            color: white;
            padding: 0.375rem 0.875rem;
            border-radius: 20px;
            font-size: 0.8rem;
            font-weight: 600;
            box-shadow: var(--shadow-sm);
        }

        /* Video Modal */
        .video-modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(30, 41, 59, 0.95);
            backdrop-filter: blur(20px);
            z-index: 2000;
            animation: fadeIn 0.3s ease;
        }

        .video-modal.active {
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .modal-content {
            position: relative;
            width: 90%;
            max-width: 900px;
            background: var(--bg-white);
            border-radius: 20px;
            overflow: hidden;
            animation: slideUp 0.3s ease;
            box-shadow: var(--shadow-xl);
        }

        .modal-header {
            padding: 1.5rem;
            background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .modal-title {
            font-size: 1.3rem;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 0.75rem;
            color: white;
        }

        .modal-title .youtube-icon {
            color: #ff0000;
        }

        .close-modal {
            background: rgba(255, 255, 255, 0.2);
            border: none;
            color: white;
            font-size: 1.5rem;
            cursor: pointer;
            transition: var(--transition);
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .close-modal:hover {
            background: rgba(255, 255, 255, 0.3);
            transform: rotate(90deg);
        }

        .video-player {
            width: 100%;
            height: 500px;
            background: #000;
            position: relative;
        }

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

        .video-placeholder {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            height: 100%;
            color: var(--text-secondary);
        }

        .video-placeholder i {
            font-size: 4rem;
            margin-bottom: 1rem;
            color: var(--primary-color);
        }

        /* Load More Button */
        .load-more {
            text-align: center;
            padding: 3rem 0;
        }

        .load-more-btn {
            padding: 1rem 2.5rem;
            background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
            border: none;
            border-radius: 12px;
            color: white;
            font-size: 1rem;
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            position: relative;
            overflow: hidden;
            box-shadow: var(--shadow-md);
        }

        .load-more-btn:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-xl);
        }

        .load-more-btn:active {
            transform: translateY(-1px);
        }

        /* Loading Spinner */
        .spinner {
            display: none;
            width: 50px;
            height: 50px;
            border: 3px solid var(--border-color);
            border-top-color: var(--primary-color);
            border-radius: 50%;
            animation: spin 1s linear infinite;
            margin: 2rem auto;
        }

        @keyframes spin {
            to {
                transform: rotate(360deg);
            }
        }

        .spinner.active {
            display: block;
        }

        /* Toast Notification */
        .toast {
            position: fixed;
            bottom: 30px;
            right: 30px;
            background: var(--bg-white);
            color: var(--text-primary);
            padding: 1rem 1.5rem;
            border-radius: 12px;
            box-shadow: var(--shadow-lg);
            transform: translateX(400px);
            transition: transform 0.3s ease;
            z-index: 3000;
            display: flex;
            align-items: center;
            gap: 1rem;
            border-left: 4px solid var(--primary-color);
        }

        .toast.show {
            transform: translateX(0);
        }

        .toast i {
            color: var(--primary-color);
            font-size: 1.2rem;
        }

        /* Animations */
        @keyframes fadeIn {
            from {
                opacity: 0;
            }

            to {
                opacity: 1;
            }
        }

        @keyframes slideUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }

            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .gallery-title h1 {
                font-size: 2rem;
            }

            .gallery-wrapper {
                margin: 1rem auto;
            }

            .controls {
                flex-direction: column;
                padding: 1rem;
            }

            .search-box {
                max-width: 100%;
            }

            .video-grid {
                grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
                gap: 1rem;
            }

            .video-player {
                height: 300px;
            }

            .modal-content {
                width: 95%;
                margin: 1rem;
            }
        }

        @media (max-width: 480px) {
            .video-grid {
                grid-template-columns: 1fr;
            }

            .filter-buttons {
                width: 100%;
                justify-content: center;
            }
        }

        /* No Results Message */
        .no-results {
            grid-column: 1/-1;
            text-align: center;
            padding: 3rem;
            color: var(--text-secondary);
        }

        .no-results i {
            font-size: 3rem;
            margin-bottom: 1rem;
            color: var(--primary-color);
        }

        /* Course Badge */
        .course-badge {
            position: absolute;
            top: 10px;
            right: 10px;
            background: var(--primary-color);
            color: white;
            padding: 0.3rem 0.6rem;
            border-radius: 6px;
            font-size: 0.75rem;
            font-weight: 600;
        }

        /* Responsive Adjustments */
        @media (max-width: 992px) {
            .gallery-wrapper {
                margin-top: 1rem;
                padding: 0 4%;
            }

            .gallery-title h1 {
                font-size: 2rem;
            }

            .controls {
                flex-direction: column;
                align-items: stretch;
            }
        }

        @media (max-width: 768px) {
            .gallery-title h1 {
                font-size: 1.6rem;
            }

            .gallery-title p {
                font-size: 0.95rem;
            }

            .filter-buttons,
            .view-toggle {
                justify-content: center;
            }

            .photo-grid,
            .video-grid {
                grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            }
        }

        @media (max-width: 480px) {
            .gallery-title h1 {
                font-size: 1.4rem;
            }

            .gallery-title p {
                font-size: 0.85rem;
            }

            .controls {
                padding: 1rem;
            }

            .filter-btn {
                padding: 0.5rem 1rem;
                font-size: 0.8rem;
            }

            .search-box input {
                font-size: 0.9rem;
            }
        }