.main-content {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 350px;
    gap: 64px;
    align-items: start;
    margin-top: -200px;
    position: relative;
    z-index: 1;
}

/* Hero Section */
.hero {
    background-color: #e8f0fe;
    padding: 48px 0 48px;
    margin-bottom: 0;
    position: relative;
}

.hero-text {
    max-width: 720px;
}

    .hero-text h1 {
        font-size: 40px;
        font-weight: 700;
        color: #111;
        margin-bottom: 16px;
        line-height: 1.2;
    }

    .hero-text p {
        font-size: 16px;
        color: #555;
        line-height: 1.6;
        max-width: 600px;
    }

.description p {
    max-height: 4.5em;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

    .description p.expanded {
        max-height: 1000px;
        /* large enough to show full text */
    }

/* Course Content */
.course-content {
    margin-top: 230px;
    background: #fff;
    border-radius: 12px;
    padding: 32px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

/* Sticky Course Card */
.course-card-wrapper {
    position: sticky;
    top: 24px;
    margin-top: 0;
}

/* Course Card */
.course-card {
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    padding: 24px;
    position: sticky;
    top: 24px;
}

.course-thumbnail {
    position: relative;
    width: 100%;
    padding-top: 56.25%;
    border-radius: 8px;
    overflow: hidden;
    margin-bottom: 24px;
    background: #f8f9fa;
}

    .course-thumbnail img {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        object-fit: cover;
    }

.play-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 56px;
    height: 56px;
    background: rgba(0, 0, 0, 0.75);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: transform 0.2s ease;
}

    .play-button:hover {
        transform: translate(-50%, -50%) scale(1.1);
    }

    .play-button svg {
        width: 24px;
        height: 24px;
        fill: #fff;
        margin-left: 4px;
    }

.price {
    font-size: 28px;
    font-weight: 700;
    color: #111;
    margin-bottom: 12px;
}

.time-left {
    font-size: 15px;
    color: #666;
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 8px;
}

    .time-left svg {
        width: 16px;
        height: 16px;
        color: #666;
    }

.cta-button {
    gap: 6px;
    justify-content: center;
    display: flex;
    width: 100%;
    padding: 14px;
    background: #0066ff;
    color: #fff;
    text-align: center;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    margin-bottom: 12px;
    transition: all 0.2s ease;
    border: none;
    cursor: pointer;
}

    .cta-button:hover {
        background: #0052cc;
        transform: translateY(-1px);
    }

.buy-now {
    display: block;
    width: 100%;
    padding: 14px;
    background: #fff;
    color: #111;
    text-align: center;
    border: 1px solid #ddd;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s ease;
    margin-bottom: 24px;
}

    .buy-now:hover {
        background: #f8f9fa;
        border-color: #ccc;
    }

.course-features {
    padding-top: 24px;
    border-top: 1px solid #eee;
}

    .course-features h3 {
        font-size: 17px;
        font-weight: 600;
        color: #111;
        margin-bottom: 16px;
    }

.features-list {
    list-style: none;
    margin: 0;
    padding: 0;
}

    .features-list li {
        font-size: 14px;
        color: #555;
        margin-bottom: 12px;
        display: flex;
        align-items: flex-start;
        gap: 8px;
        line-height: 1.4;
    }

        .features-list li::before {
            content: '•';
            color: #111;
            font-weight: bold;
            margin-top: -2px;
        }

/* Course Content */
.course-content {
    background: #fff;
    border-radius: 12px;
    padding: 32px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.content-header {
    margin-bottom: 24px;
}

    .content-header h2 {
        font-size: 24px;
        font-weight: 600;
        color: #111;
        margin-bottom: 8px;
    }

.content-stats {
    font-size: 14px;
    color: #666;
    display: flex;
    align-items: center;
    gap: 16px;
}

    .content-stats span {
        position: relative;
        padding-right: 0;
    }

        .content-stats span:not(:last-child)::after {
            content: '';
            position: absolute;
            right: -8px;
            top: 50%;
            transform: translateY(-50%);
            width: 4px;
            height: 4px;
            background: #666;
            border-radius: 50%;
        }

.lessons-list {
    border: 1px solid #eee;
    border-radius: 8px;
    background: #fff;
    overflow: hidden;
}

.lesson-section {
    border-bottom: 1px solid #eee;
}

    .lesson-section:last-child {
        border-bottom: none;
    }

.section-header {
    padding: 16px 20px;
    background: #f8f9fa;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
    transition: background-color 0.2s ease;
}

    .section-header:hover {
        background: #f1f3f5;
    }

    .section-header h3 {
        font-size: 16px;
        font-weight: 500;
        color: #111;
    }

    .section-header .section-meta {
        font-size: 14px;
        color: #666;
    }

.lesson-item {
    padding: 14px 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    border-top: 1px solid #eee;
    transition: background-color 0.2s ease;
    cursor: pointer;
}

    .lesson-item:hover {
        background: #f8f9fa;
    }

    .lesson-item svg {
        width: 20px;
        height: 20px;
        color: #666;
        flex-shrink: 0;
    }

.lesson-info {
    flex: 1;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
}

.lesson-title {
    font-size: 14px;
    color: #333;
    font-weight: 500;
}

.lesson-duration {
    font-size: 14px;
    color: #666;
    flex-shrink: 0;
}

.lesson-preview {
    color: #0066ff;
    font-size: 14px;
    font-weight: 500;
    margin-left: auto;
    text-decoration: none;
}

    .lesson-preview:hover {
        text-decoration: underline;
    }

/* Requirements Section */
.requirements {
    padding: 48px 0;
    border-top: 1px solid #eee;
}

    .requirements h2 {
        font-size: 24px;
        font-weight: 600;
        color: #111;
        margin-bottom: 16px;
    }

    .requirements p {
        color: #555;
        margin-bottom: 24px;
    }

/* Description Section */
.description {
    padding: 48px 0;
    border-top: 1px solid #eee;
}

    .description h2 {
        font-size: 24px;
        font-weight: 600;
        color: #111;
        margin-bottom: 16px;
    }

    .description p {
        color: #555;
        margin-bottom: 16px;
    }

.show-more {
    color: #0066ff;
    text-decoration: none;
    font-weight: 500;
}

    .show-more:hover {
        text-decoration: underline;
    }

@media(max-width: 768px) {
    .course-card, .course-card-wrapper {
        position: unset;
    }

    .main-content {
        grid-template-columns: unset
    }

    .hero .container {
        padding: 0 15px;
    }

    .hero-text {
        max-width: unset;
    }

        .hero-text h1 {
            font-size: 29px;
        }

    .hero {
        padding: 48px 10px 48px;
    }

    .course-content {
        padding: 0 10px;
    }

    .course-content {
        margin-top: 200px;
    }

    .requirements, .description {
        padding: 20px 0;
    }

    .main-content {
        gap: 20px;
    }

    .course-card {
        padding: 10px;
    }
}

/* Video Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    z-index: 1000;
    backdrop-filter: blur(5px);
}

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

.modal-content {
    background: white;
    border-radius: 16px;
    overflow: hidden;
    max-width: 900px;
    width: 90%;
    max-height: 90%;
    position: relative;
}

.modal-header {
    padding: 1.5rem 2rem;
    border-bottom: 1px solid #eee;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-title {
    font-size: 1.2rem;
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: background-color 0.2s;
}

    .close-btn:hover {
        background: #f8f9fa;
    }