/* This is the crucial fix for the hidden header */
.lesson-container { 
    max-width: 1100px; 
    margin: 0 auto; 
    padding: 100px 20px 40px 20px; 
}

.lesson-title-area {
    border-bottom: 1px solid rgba(255, 111, 111, 0.2);
    padding-bottom: 20px;
    margin-bottom: 30px;
}

.lesson-title-area h1 {
    color: #ff6f6f;
    margin: 0;
    font-size: 2.2rem;
}

/* Featured Video Section */
.main-video-section {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: 25px;
    margin-bottom: 50px;
}

.video-player-box {
    background: #000;
    border-radius: 15px;
    overflow: hidden;
    position: relative;
    padding-bottom: 56.25%; /* 16:9 */
    height: 0;
    box-shadow: 0 15px 35px rgba(0,0,0,0.4);
}

.video-player-box iframe {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: none;
}

.topper-insight-card {
    background: rgba(255, 111, 111, 0.08);
    border: 1px solid rgba(255, 111, 111, 0.3);
    padding: 25px;
    border-radius: 15px;
    height: fit-content;
}

/* Playlist Grid */
.playlist-header {
    margin-bottom: 25px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 25px;
}

.playlist-card {
    background: rgba(255,255,255,0.03);
    border-radius: 15px;
    overflow: hidden;
    border: 1px solid rgba(255,255,255,0.1);
    transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.playlist-card:hover {
    border-color: #ff6f6f;
    transform: translateY(-8px);
    background: rgba(255,255,255,0.06);
}

.thumbnail-wrap {
    position: relative;
    padding-bottom: 56.25%;
    background: #000;
}

.thumbnail-wrap iframe {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: none;
}

.card-content { padding: 20px; }
.card-content h4 { margin: 0; color: #ff6f6f; font-size: 1.1rem; }
.card-content p { font-size: 0.9rem; margin: 10px 0 0; opacity: 0.7; line-height: 1.4; }

@media (max-width: 900px) {
    .main-video-section { grid-template-columns: 1fr; }
    .lesson-container { padding-top: 80px; }
    .lesson-title-area h1 { font-size: 1.8rem; }
}