.lessons-container {
        display: grid;
        grid-template-columns: 1fr 350px;
        gap: 30px;
        margin-top: 40px;
    }
        
        .video-container {
            position: relative;
            padding-bottom: 56.25%;
            height: 0;
            overflow: hidden;
            border-radius: 10px;
            box-shadow: var(--shadow);
        }
        
        .video-container iframe {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            border: none;
        }
        
        .playlist {
            background: var(--card-bg);
            border-radius: 10px;
            padding: 20px;
            box-shadow: var(--shadow);
            max-height: 600px;
            overflow-y: auto;
        }
        
        .playlist h3 {
            margin-bottom: 20px;
            color: var(--primary-color);
            text-align: center;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--math-color);
        }
        
        .lesson-item {
            display: flex;
            align-items: center;
            padding: 12px;
            margin-bottom: 10px;
            background: var(--bg-color);
            border-radius: 8px;
            cursor: pointer;
            transition: var(--transition);
        }
        
        .lesson-item:hover {
            background: var(--math-color);
            color: white;
        }
        
        .lesson-item.active {
            background: var(--math-color);
            color: white;
        }
        
        .lesson-number {
            background: var(--math-color);
            color: white;
            width: 30px;
            height: 30px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-left: 10px;
            font-weight: bold;
        }
        
        .lesson-item.active .lesson-number {
            background: white;
            color: var(--math-color);
        }
        
        .lesson-title {
            flex: 1;
            font-size: 0.95rem;
        }
        
        .lesson-thumbnail {
            width: 60px;
            height: 40px;
            border-radius: 4px;
            margin-left: 10px;
            object-fit: cover;
        }
        
        
        
        .loading {
            text-align: center;
            padding: 20px;
            color: var(--text-color);
        }
        
        .error {
            text-align: center;
            padding: 20px;
            color: #e63946;
            background: #ffebee;
            border-radius: 8px;
            margin: 20px 0;
        }
        
        .section-title {
            text-align: center;
            margin-bottom: 50px;
        }

        .section-title h2 {
            font-size: 2.2rem;
            color: var(--primary-color);
            margin-bottom: 15px;
        }

        #math-lessons {
            padding: 100px 0 60px;
        }

        /* فلترة الدروس */
        .filters {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            margin-bottom: 20px;
            justify-content: center;
        }
        
        .filter-btn {
            padding: 8px 16px;
            background: var(--bg-color);
            border: 1px solid var(--arabic-color);
            border-radius: 20px;
            cursor: pointer;
            font-size: 0.9rem;
            color: var(--text-color);
        }
        
        .filter-btn.active {
            background: var(--arabic-color);
            color: white;
        }
        
        .filter-btn:hover {
            background: var(--arabic-color);
            color: white;
        }

    @media (max-width: 992px) {
        .lessons-container {
            grid-template-columns: 1fr; 
        }
        
        .playlist {
            order: 1; 
            max-height: 400px;
        }
        
        .main-video {
            order: 0; 
        }
    }
    
    @media (max-width: 576px) {
        .playlist {
            max-height: 350px; 
        }
        
        .lesson-item {
            padding: 10px; 
        }
        
        .lesson-title {
            font-size: 0.85rem; 
        }
        
        .lesson-thumbnail {
            width: 50px; 
            height: 35px;
        }
                    .filters {
                flex-direction: column;
            }
            
            .filter-btn {
                width: 100%;
                text-align: center;
            }
        }