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

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background-color: #f7f7f7;
            color: #333;
        }

        /* Header */
        header {
            background: white;
            padding: 1rem 0;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
            position: sticky;
            top: 0;
            z-index: 100;
        }

        .course-layout {
            align-items: flex-start;
        }

        .sidebar {
            margin-top: -60%;
        }

        .navbar {
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 2rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-size: 1.5rem;
            font-weight: bold;
            color: #1f1f1f;
        }

        .logo span {
            color: #a435f0;
        }

        /* Hero Section */
        .hero {
            background: #7d66ea;
            color: white;
            padding: 2rem 0;
        }

        .hero-content {
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 2rem;
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 3rem;
            align-items: center;
        }

        .hero-text h1 {
            font-size: 2.5rem;
            margin-bottom: 1rem;
            line-height: 1.2;
        }

        .hero-text p {
            font-size: 1.1rem;
            margin-bottom: 2rem;
            opacity: 0.95;
        }

        .rating {
            display: flex;
            align-items: center;
            gap: 1rem;
            margin-bottom: 1.5rem;
            font-size: 0.95rem;
        }

        .stars {
            color: #ffc107;
            display: flex;
            gap: 0.25rem;
        }

        /* Main Content */
        .container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 2rem;
        }

        .course-layout {
            display: grid;
            grid-template-columns: 2fr 1fr;
            gap: 2rem;
            margin-top: -3rem;
            position: relative;
            z-index: 10;
        }

        /* Tabs Section */
        .tabs-container {
            background: white;
            border-radius: 8px;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
            overflow: hidden;
        }

        .tabs-header {
            display: flex;
            border-bottom: 2px solid #eee;
            background: #fafafa;
        }

        .tab-button {
            flex: 1;
            padding: 1rem;
            background: none;
            border: none;
            font-size: 1rem;
            font-weight: 600;
            color: #565656;
            cursor: pointer;
            transition: all 0.3s;
            position: relative;
        }

        .tab-button:hover {
            background: white;
        }

        .tab-button.active {
            color: #7d66ea;
            background: white;
        }

        .tab-button.active::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            right: 0;
            height: 2px;
            background: #7d66ea;
        }

        .tabs-content {
            padding: 2rem;
        }

        .tab-pane {
            display: none;
        }

        .tab-pane.active {
            display: block;
            animation: fadeIn 0.3s;
        }

        @keyframes fadeIn {
            from {
                opacity: 0;
            }

            to {
                opacity: 1;
            }
        }

        /* Overview Tab */
        .overview-content p {
            line-height: 1.6;
            color: #565656;
            margin-bottom: 1rem;
        }

        .skills {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            margin: 1.5rem 0;
        }

        .skill-badge {
            background: #7d66ea;
            color: white;
            padding: 0.5rem 1rem;
            border-radius: 20px;
            font-size: 0.85rem;
            font-weight: 500;
        }

        /* Curriculum Tab */
        .accordion {
            border: 1px solid #ddd;
            border-radius: 8px;
            overflow: hidden;
        }

        .accordion-item {
            border-bottom: 1px solid #ddd;
        }

        .accordion-item:last-child {
            border-bottom: none;
        }

        .accordion-header {
            background: #fafafa;
            padding: 1rem;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-weight: 600;
            color: #1f1f1f;
            transition: background 0.3s;
            border: none;
            width: 100%;
            text-align: left;
        }

        .accordion-header:hover {
            background: #f0f0f0;
        }

        .accordion-header.active {
            background: #f0f0f0;
        }

        .accordion-header i {
            transition: transform 0.3s;
        }

        .accordion-content {
            display: none;
            padding: 1rem;
            background: white;
        }

        .accordion-content.active {
            display: block;
        }

        .accordion-content ul {
            list-style: none;
        }

        .accordion-content li {
            padding: 0.5rem 0;
            color: #565656;
        }

        .accordion-content li i {
            margin-right: 0.75rem;
            color: #7d66ea;
        }

        /* Instructor Tab */
        .instructor {
            display: flex;
            gap: 2rem;
        }

        .video-placeholder {
            position: relative;
            cursor: pointer;
            border-radius: 1px;
            overflow: hidden;
        }

        .video-thumb {
            width: 100%;
            height: auto;
            display: block;
        }

        .play-overlay {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            background: rgba(0, 0, 0, 0.5);
            color: #fff;
            padding: 15px 20px;
            border-radius: 50%;
            font-size: 1.5rem;
        }

        .video-frame iframe {
            border-radius: 10px;
        }

        .instructor-img {
            width: 120px;
            height: 120px;
            border-radius: 50%;
            background: #7d66ea;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-size: 3rem;
            flex-shrink: 0;
        }

        .instructor-info h3 {
            margin-bottom: 0.5rem;
            color: #1f1f1f;
            font-size: 1.3rem;
        }

        .instructor-info p {
            line-height: 1.6;
            color: #565656;
            margin-bottom: 1rem;
        }

        .instructor-stats {
            display: flex;
            gap: 2rem;
            font-size: 0.95rem;
            margin: 1rem 0;
            flex-wrap: wrap;
        }

        .instructor-stats span {
            color: #565656;
        }

        .instructor-stats i {
            color: #7d66ea;
            margin-right: 0.5rem;
        }

        /* Right Sidebar */
        .sidebar {
            /* position: sticky; */
            top: 100px;
        }

        .course-card {
            background: white;
            border-radius: 8px;
            overflow: hidden;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        }

        .video-placeholder {
            width: 100%;
            aspect-ratio: 16/9;
            background: #7d66ea;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-size: 3rem;
        }

        .price-section {
            padding: 1.5rem;
            border-bottom: 1px solid #ddd;
        }

        .price {
            font-size: 2rem;
            font-weight: bold;
            color: #1f1f1f;
        }

        .original-price {
            text-decoration: line-through;
            color: #999;
            font-size: 1.1rem;
            margin-left: 0.5rem;
        }

        .discount {
            color: #c41e3a;
            font-weight: 600;
            font-size: 0.9rem;
            margin-top: 0.5rem;
        }

        .enroll-btn {
            width: 100%;
            padding: 1rem;
            background: #7d66ea;
            color: white;
            border: none;
            font-size: 1rem;
            font-weight: 600;
            cursor: pointer;
            transition: transform 0.2s, box-shadow 0.2s;
        }

        .enroll-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 16px rgba(102, 126, 234, 0.4);
        }

        .course-info {
            padding: 1.5rem;
        }

        .info-item {
            display: flex;
            align-items: center;
            padding: 0.75rem 0;
            border-bottom: 1px solid #eee;
            font-size: 0.9rem;
        }

        .info-item:last-child {
            border-bottom: none;
        }

        .info-item i {
            width: 25px;
            color: #7d66ea;
            margin-right: 1rem;
        }

        .info-item-label {
            color: #565656;
            flex: 1;
        }

        .info-item-value {
            font-weight: 600;
            color: #1f1f1f;
        }

        .share-btn {
            width: 100%;
            padding: 0.75rem;
            background: white;
            border: 1px solid #ddd;
            color: #7d66ea;
            font-weight: 600;
            cursor: pointer;
            border-radius: 4px;
            margin-top: 1rem;
            transition: background 0.3s;
        }

        .share-btn:hover {
            background: #f9f9f9;
        }

        /* Responsive */
        @media (max-width: 768px) {
            .hero-content {
                grid-template-columns: 1fr;
            }

            .hero-text h1 {
                font-size: 1.8rem;
            }

            .course-layout {
                grid-template-columns: 1fr;
                margin-top: 0;
            }

            .sidebar {
                position: static;
            }

            .tabs-header {
                overflow-x: auto;
                flex-wrap: nowrap;
            }

            .tab-button {
                white-space: nowrap;
            }
        }