/* Course Detail Premium Styles */

:root {
    --course-primary: #06b6d4;
    --course-secondary: #10b981;
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(6, 182, 212, 0.15);
    --player-bg: #0f172a;
}

/* Immersive Course Header */
.courses-header {
    background: linear-gradient(135deg, #f0fdfa 0%, #e0f2fe 100%);
    padding: 100px 0 120px;
    position: relative;
    border-bottom: 1px solid rgba(0,0,0,0.05);
    text-align: center;
}

.courses-header .badge {
    background: rgba(16, 185, 129, 0.1) !important;
    color: var(--course-secondary) !important;
    border: 1px solid rgba(16, 185, 129, 0.2);
}

.courses-header h1 {
    font-size: 4rem;
    font-weight: 900;
    color: #0f172a;
    margin-bottom: 20px;
}

.course-hero {
    position: relative;
    padding: 80px 0 140px;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    color: white;
    overflow: hidden;
}

.course-hero::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: radial-gradient(circle at 70% 30%, rgba(6, 182, 212, 0.15) 0%, transparent 50%);
    pointer-events: none;
}

.course-content-wrapper {
    margin-top: -120px;
    position: relative;
    z-index: 100;
}

/* Ensure equal top alignment for both columns */
.course-detail-page .row.g-5 {
    align-items: flex-start;
}

.article-sidebar-sticky {
    position: sticky;
    top: 120px;
    margin-top: 0; /* Prevents any offset from the main content */
}
    background: var(--glass-bg);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.08);
}

.sidebar-sticky {
    position: sticky;
    top: 100px;
}

/* Video Player Styles */
.video-player-section {
    background: var(--player-bg);
    border-radius: 24px;
    overflow: hidden;
    position: relative;
    box-shadow: 0 20px 40px rgba(0,0,0,0.3);
    margin-bottom: 40px;
    width: 100%;
}

.video-aspect-ratio-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* 16:9 Aspect Ratio */
    height: 0;
}

.video-container,
.video-placeholder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 5;
}

.video-container video {
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: black;
}

.video-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background-size: cover;
    background-position: center;
    color: white;
    text-align: center;
    z-index: 10;
    background-image: linear-gradient(rgba(15, 23, 42, 0.7), rgba(15, 23, 42, 0.8)), var(--placeholder-url);
}

/* Curriculum List Styles */
.curriculum-item {
    border: none;
    border-radius: 18px !important;
    margin-bottom: 12px;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    background: #ffffff;
    border: 1px solid #f1f5f9;
    cursor: pointer;
}

.curriculum-item:hover {
    border-color: var(--course-primary);
    transform: translateX(-8px);
    box-shadow: 0 10px 20px rgba(6, 182, 212, 0.1);
}

.curriculum-item.active {
    background: rgba(6, 182, 212, 0.05);
    border-color: var(--course-primary);
}

.video-icon {
    width: 44px; height: 44px;
    display: grid; place-items: center;
    border-radius: 12px;
    background: #f8fafc;
    color: var(--course-primary);
    transition: all 0.3s ease;
    flex-shrink: 0;
}

.curriculum-item:hover .video-icon {
    background: var(--course-primary);
    color: white;
}

/* Sidebar Feature Icons */
.course-feature-icon {
    width: 32px;
    height: 32px;
    display: grid;
    place-items: center;
    background: rgba(13, 110, 253, 0.08);
    color: var(--course-primary);
    border-radius: 8px;
    font-size: 0.9rem;
    flex-shrink: 0;
}

/* UI Elements */
.price-tag {
    font-size: 2.5rem; font-weight: 900;
    background: linear-gradient(135deg, var(--course-primary), var(--course-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.feature-pill {
    background: white; border: 1px solid #f1f5f9;
    padding: 14px 20px; border-radius: 16px;
    margin-bottom: 12px; display: flex; align-items: center;
    font-size: 0.95rem; color: #475569;
    transition: all 0.3s ease;
}

.feature-pill:hover { border-color: var(--course-primary); background: #f8fafc; }

.feature-pill i { color: var(--course-primary); margin-left: 15px; font-size: 1.2rem; }

.badge-status { padding: 8px 18px; border-radius: 100px; font-weight: 800; font-size: 0.8rem; }

.pulse-animation {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); box-shadow: 0 0 0 0 rgba(6, 182, 212, 0.4); }
    70% { transform: scale(1.05); box-shadow: 0 0 0 15px rgba(6, 182, 212, 0); }
    100% { transform: scale(1); box-shadow: 0 0 0 0 rgba(6, 182, 212, 0); }
}