/* 
   5th Semester Course Portal - CSS Stylesheet
   Designed with premium glassmorphism, responsive grid layouts, and interactive micro-animations.
*/

/* --- CSS Variables & Design Tokens --- */
:root {
    /* Color Palette - Transitioned to Brand Royal Blue Theme */
    --bg-dark: #0b1121; /* Rich midnight navy */
    --bg-card: rgba(22, 38, 77, 0.45); /* Premium royal blue glass card background */
    --bg-card-hover: rgba(30, 52, 105, 0.6);
    --border-glass: rgba(255, 255, 255, 0.11);
    --border-glass-hover: rgba(255, 255, 255, 0.22);
    
    --text-primary: #ffffff;
    --text-secondary: #cdd7f0;
    --text-muted: #7f92be;
    
    /* Course Colors (HSL) - Synced with Blue Theme */
    --color-all: #3F67C6; /* Brand Blue */
    --color-all-glow: rgba(63, 103, 198, 0.45);
    
    --color-psd300: #3b82f6; /* Experimental Psychology - Blue */
    --color-psd300-glow: rgba(59, 130, 246, 0.3);
    
    --color-psd305: #93c5fd; /* Cognitive Psychology - Light Ice Blue */
    --color-psd305-glow: rgba(147, 197, 253, 0.3);
    
    --color-psd310: #06b6d4; /* Psychometrics - Teal/Cyan */
    --color-psd310-glow: rgba(6, 182, 212, 0.3);
    
    --color-psd315: #38bdf8; /* Health Psychology - Sky Blue */
    --color-psd315-glow: rgba(56, 189, 248, 0.3);
    
    --color-psd320: #fbbf24; /* Psychology of Learning - Amber/Orange */
    --color-psd320-glow: rgba(251, 191, 36, 0.3);

    /* Fonts & Radii */
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --radius-full: 9999px;
    
    /* Dynamic Transitions */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* --- Base Reset & Setup --- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: var(--font-body);
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
    /* Soft blue linear overlay */
    background-image: radial-gradient(circle at 50% 0%, #15244d 0%, #0b1121 100%);
}

/* Decorative Ambient Blobs */
.bg-gradient-circle {
    position: fixed;
    border-radius: var(--radius-full);
    filter: blur(120px);
    z-index: 0;
    pointer-events: none;
    opacity: 0.5;
    mix-blend-mode: screen;
}

.blob-1 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(63, 103, 198, 0.4) 0%, rgba(0,0,0,0) 70%);
    top: -10%;
    right: -5%;
}

.blob-2 {
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.3) 0%, rgba(0,0,0,0) 70%);
    bottom: -15%;
    left: -10%;
}

.blob-3 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.2) 0%, rgba(0,0,0,0) 70%);
    top: 40%;
    left: 45%;
}

/* --- Layout Container --- */
.app-container {
    display: flex;
    min-height: 100vh;
    position: relative;
    z-index: 1;
}

/* --- Sidebar Navigation --- */
.sidebar {
    width: 280px;
    background: rgba(12, 21, 46, 0.8);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border-right: 1px solid var(--border-glass);
    padding: 2rem 1.5rem;
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    z-index: 10;
}

.sidebar-brand {
    margin-bottom: 3rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.sidebar-brand img {
    max-width: 100%;
    height: auto;
    max-height: 50px;
    filter: drop-shadow(0 0 10px rgba(255, 255, 255, 0.2));
    transition: transform var(--transition-bounce);
}

.sidebar-brand img:hover {
    transform: scale(1.05);
}

.sidebar-menu {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.menu-section h3 {
    font-family: var(--font-heading);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 1rem;
    padding-left: 0.5rem;
}

.course-selector-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.course-selector-list li {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.85rem 1rem;
    border-radius: var(--radius-md);
    cursor: pointer;
    background: transparent;
    border: 1px solid transparent;
    transition: all var(--transition-fast);
}

.course-selector-list li:hover {
    background: rgba(255, 255, 255, 0.03);
    border-color: rgba(255, 255, 255, 0.05);
}

.course-dot {
    width: 10px;
    height: 10px;
    border-radius: var(--radius-full);
    flex-shrink: 0;
}

.course-name {
    font-family: var(--font-heading);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

.course-selector-list li:hover .course-name {
    color: var(--text-primary);
}

/* Dots Coloring & Glows */
.dot-all { background-color: var(--color-all); box-shadow: 0 0 8px var(--color-all-glow); }
.dot-psd300 { background-color: var(--color-psd300); box-shadow: 0 0 8px var(--color-psd300-glow); }
.dot-psd305 { background-color: var(--color-psd305); box-shadow: 0 0 8px var(--color-psd305-glow); }
.dot-psd310 { background-color: var(--color-psd310); box-shadow: 0 0 8px var(--color-psd310-glow); }
.dot-psd315 { background-color: var(--color-psd315); box-shadow: 0 0 8px var(--color-psd315-glow); }
.dot-psd320 { background-color: var(--color-psd320); box-shadow: 0 0 8px var(--color-psd320-glow); }

/* Active Course State Styling */
.course-selector-list li.active-course[data-course="all"] { background: rgba(63, 103, 198, 0.12); border-color: rgba(63, 103, 198, 0.3); }
.course-selector-list li.active-course[data-course="psd300"] { background: rgba(59, 130, 246, 0.12); border-color: rgba(59, 130, 246, 0.3); }
.course-selector-list li.active-course[data-course="psd305"] { background: rgba(147, 197, 253, 0.12); border-color: rgba(147, 197, 253, 0.3); }
.course-selector-list li.active-course[data-course="psd310"] { background: rgba(6, 182, 212, 0.12); border-color: rgba(6, 182, 212, 0.3); }
.course-selector-list li.active-course[data-course="psd315"] { background: rgba(56, 189, 248, 0.12); border-color: rgba(56, 189, 248, 0.3); }
.course-selector-list li.active-course[data-course="psd320"] { background: rgba(251, 191, 36, 0.12); border-color: rgba(251, 191, 36, 0.3); }

.course-selector-list li.active-course .course-name {
    color: var(--text-primary);
    font-weight: 600;
}

.footer-links {
    margin-top: auto;
    border-top: 1px solid var(--border-glass);
    padding-top: 1.5rem;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.back-link:hover {
    color: var(--color-all);
}

/* --- Main Dashboard Content Layout --- */
.main-content {
    margin-left: 280px;
    flex: 1;
    padding: 2.5rem 3rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

/* Header Area */
.dashboard-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
}

.header-title-area h1 {
    font-family: var(--font-heading);
    font-size: 2.25rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #ffffff 40%, #93c5fd 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.4rem;
}

.header-title-area .subtitle {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 400;
}

.search-box {
    position: relative;
    width: 380px;
}

.search-box i {
    position: absolute;
    left: 1.15rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 0.95rem;
    pointer-events: none;
    transition: color var(--transition-fast);
}

.search-box input {
    width: 100%;
    background: rgba(15, 17, 28, 0.6);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-lg);
    padding: 0.95rem 1.15rem 0.95rem 2.8rem;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 0.9rem;
    font-weight: 400;
    outline: none;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    transition: all var(--transition-smooth);
}

.search-box input:focus {
    border-color: rgba(63, 103, 198, 0.5);
    background: rgba(15, 17, 28, 0.85);
    box-shadow: 0 0 15px rgba(63, 103, 198, 0.15);
}

.search-box input:focus + i {
    color: var(--color-all);
}

/* Timeline Weeks Section */
.timeline-section {
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-lg);
    padding: 1.5rem 1.75rem;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.25rem;
}

.section-header h2 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

.section-header h2 i {
    color: var(--color-all);
}

.clear-filters-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: color var(--transition-fast);
}

.clear-filters-btn:hover {
    color: var(--text-primary);
}

.timeline-container {
    width: 100%;
    overflow: hidden;
}

.timeline-scroll {
    display: flex;
    gap: 0.6rem;
    overflow-x: auto;
    padding-bottom: 0.5rem;
    scrollbar-width: thin;
    scrollbar-color: rgba(255, 255, 255, 0.1) transparent;
}

/* Custom horizontal scrollbar for timeline */
.timeline-scroll::-webkit-scrollbar {
    height: 4px;
}

.timeline-scroll::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-full);
}

.timeline-scroll::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.25);
}

.timeline-week-btn {
    flex-shrink: 0;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: var(--radius-md);
    padding: 0.65rem 1.15rem;
    color: var(--text-secondary);
    font-family: var(--font-heading);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.timeline-week-btn:hover {
    background: rgba(255, 255, 255, 0.07);
    color: var(--text-primary);
    border-color: rgba(255, 255, 255, 0.12);
}

.timeline-week-btn.active {
    background: var(--color-all);
    color: #ffffff;
    border-color: var(--color-all);
    box-shadow: 0 4px 15px var(--color-all-glow);
}

/* Active Filters Display */
.active-filters-bar {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-top: -1.25rem;
    padding: 0 0.5rem;
}

.filter-label {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.filters-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.filter-tag {
    background: rgba(63, 103, 198, 0.15);
    border: 1px solid rgba(63, 103, 198, 0.3);
    border-radius: var(--radius-full);
    padding: 0.3rem 0.75rem;
    font-size: 0.75rem;
    font-weight: 500;
    color: #93c5fd;
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
}

.filter-tag i {
    cursor: pointer;
    opacity: 0.7;
    transition: opacity var(--transition-fast);
}

.filter-tag i:hover {
    opacity: 1;
}

/* --- Lessons Section Grid --- */
.lessons-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.section-title-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.section-title-bar h2 {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    font-weight: 700;
}

.results-counter {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Loading Spinner State */
.loading-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 5rem 0;
    gap: 1.25rem;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid rgba(63, 103, 198, 0.15);
    border-top: 3px solid var(--color-all);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-state p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* Empty State */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 6rem 2rem;
    text-align: center;
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-lg);
    gap: 0.75rem;
}

.empty-state i {
    font-size: 3rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.empty-state h3 {
    font-family: var(--font-heading);
    font-size: 1.2rem;
    font-weight: 600;
}

.empty-state p {
    font-size: 0.9rem;
    color: var(--text-muted);
    max-width: 320px;
}

/* Main Grid */
.lessons-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

/* --- Premium Lesson Card Styling --- */
.lesson-card {
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    min-height: 250px;
    position: relative;
    overflow: hidden;
    transition: all var(--transition-smooth);
}

.lesson-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--card-accent-color, var(--color-all));
    opacity: 0.85;
    transition: width var(--transition-fast);
}

.lesson-card:hover {
    transform: translateY(-5px);
    background: var(--bg-card-hover);
    border-color: var(--border-glass-hover);
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.4), 
                0 0 20px -3px var(--card-accent-glow, var(--color-all-glow));
}

.lesson-card:hover::before {
    width: 6px;
}

.card-header-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.course-badge {
    background: var(--card-accent-badge, rgba(63, 103, 198, 0.15));
    border: 1px solid var(--card-accent-color, var(--color-all));
    color: var(--card-accent-text, #ffffff);
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-full);
    font-family: var(--font-heading);
}

.week-badge {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    font-family: var(--font-heading);
}

.card-body {
    margin-bottom: 1.5rem;
    flex: 1;
}

.lesson-title {
    font-family: var(--font-heading);
    font-size: 1.15rem;
    font-weight: 650;
    line-height: 1.4;
    color: var(--text-primary);
    margin-bottom: 0.6rem;
    /* Multiline clamping to 2 lines max */
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.lesson-description {
    font-size: 0.85rem;
    line-height: 1.5;
    color: var(--text-secondary);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-footer-actions {
    display: flex;
    gap: 0.75rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    padding-top: 1.15rem;
}

.media-play-btn {
    flex: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.65rem;
    border-radius: var(--radius-md);
    font-family: var(--font-heading);
    font-size: 0.82rem;
    font-weight: 700;
    cursor: pointer;
    border: none;
    transition: all var(--transition-fast);
}

.btn-audio-only {
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-primary);
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.btn-audio-only:hover {
    background: rgba(255, 255, 255, 0.09);
    border-color: rgba(255, 255, 255, 0.2);
}

.btn-video-play {
    background: var(--card-accent-color, var(--color-all));
    color: #ffffff;
    box-shadow: 0 4px 12px var(--card-accent-glow, var(--color-all-glow));
}

.btn-video-play:hover {
    filter: brightness(1.1);
    transform: scale(1.02);
}

/* Custom styling override properties per class injected dynamically */
.lesson-card.course-psd300 {
    --card-accent-color: var(--color-psd300);
    --card-accent-glow: var(--color-psd300-glow);
    --card-accent-badge: rgba(59, 130, 246, 0.12);
    --card-accent-text: #60a5fa;
}
.lesson-card.course-psd305 {
    --card-accent-color: var(--color-psd305);
    --card-accent-glow: var(--color-psd305-glow);
    --card-accent-badge: rgba(147, 197, 253, 0.12);
    --card-accent-text: #93c5fd;
}
.lesson-card.course-psd310 {
    --card-accent-color: var(--color-psd310);
    --card-accent-glow: var(--color-psd310-glow);
    --card-accent-badge: rgba(6, 182, 212, 0.12);
    --card-accent-text: #22d3ee;
}
.lesson-card.course-psd315 {
    --card-accent-color: var(--color-psd315);
    --card-accent-glow: var(--color-psd315-glow);
    --card-accent-badge: rgba(16, 185, 129, 0.12);
    --card-accent-text: #34d399;
}
.lesson-card.course-psd320 {
    --card-accent-color: var(--color-psd320);
    --card-accent-glow: var(--color-psd320-glow);
    --card-accent-badge: rgba(245, 158, 11, 0.12);
    --card-accent-text: #fbbf24;
}

/* --- Customized Video Modal Overlay --- */
.video-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-smooth);
}

.video-modal.active {
    opacity: 1;
    pointer-events: auto;
}

.video-modal-backdrop {
    position: absolute;
    width: 100%;
    height: 100%;
    background: rgba(4, 5, 10, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

.video-modal-content {
    position: relative;
    width: 90%;
    max-width: 960px;
    background: #0f111a;
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-lg);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.7);
    overflow: hidden;
    z-index: 101;
    transform: scale(0.9);
    transition: transform var(--transition-bounce);
}

.video-modal.active .video-modal-content {
    transform: scale(1);
}

.close-modal-btn {
    position: absolute;
    top: 1.25rem;
    right: 1.25rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.08);
    width: 36px;
    height: 36px;
    border-radius: 50%;
    color: #ffffff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 102;
    transition: all var(--transition-fast);
}

.close-modal-btn:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: rotate(90deg);
}

.video-container {
    width: 100%;
    aspect-ratio: 16/9;
    background: #000000;
}

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

.video-player-details {
    padding: 1.75rem 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.video-meta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.6rem;
}

.video-meta .badge {
    font-size: 0.7rem;
    font-weight: 700;
    padding: 0.2rem 0.6rem;
    border-radius: var(--radius-full);
    background: rgba(63, 103, 198, 0.15);
    color: #93c5fd;
    font-family: var(--font-heading);
}

.video-meta .week-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-family: var(--font-heading);
    font-weight: 600;
}

.video-player-details h3 {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.video-player-details p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* --- Floating Glassmorphic Audio Player Footer --- */
.audio-player-footer {
    position: fixed;
    bottom: 2rem;
    left: calc(50% + 140px); /* Centered considering the sidebar is 280px wide */
    transform: translateX(-50%) translateY(100px);
    width: calc(100% - 340px); /* Accommodate margins & sidebar */
    max-width: 860px;
    background: rgba(15, 17, 28, 0.75);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border: 1px solid var(--border-glass-hover);
    border-radius: var(--radius-lg);
    padding: 1rem 1.75rem;
    box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.6), 
                0 0 25px rgba(63, 103, 198, 0.15);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
    z-index: 90;
    opacity: 0;
    pointer-events: none;
    transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1), 
                opacity 0.3s ease;
}

.audio-player-footer.active {
    display: flex;
    transform: translateX(-50%) translateY(0);
    opacity: 1;
    pointer-events: auto;
}

/* Media details in audio bar */
.audio-track-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    width: 25%;
    min-width: 180px;
}

.track-artwork {
    width: 44px;
    height: 44px;
    background: rgba(63, 103, 198, 0.15);
    border: 1px solid rgba(63, 103, 198, 0.25);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #93c5fd;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.track-artwork.playing i {
    animation: bounceArt 1.2s infinite ease-in-out;
}

@keyframes bounceArt {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.15); }
}

.track-text {
    overflow: hidden;
}

.track-text h4 {
    font-family: var(--font-heading);
    font-size: 0.88rem;
    font-weight: 650;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-bottom: 0.15rem;
}

.track-text p {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

/* Audio Player Controls */
.audio-controls-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.4rem;
}

.audio-buttons {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.control-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1rem;
    cursor: pointer;
    transition: color var(--transition-fast), transform var(--transition-fast);
}

.control-btn:hover {
    color: var(--text-primary);
}

.control-btn:active {
    transform: scale(0.95);
}

.play-pause-btn {
    width: 38px;
    height: 38px;
    background: #ffffff;
    border-radius: 50%;
    color: var(--bg-dark);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.95rem;
}

.play-pause-btn:hover {
    background: #f3f4f6;
    transform: scale(1.05);
    color: var(--bg-dark);
}

.audio-progress-bar {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.time-label {
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--text-muted);
    min-width: 30px;
    text-align: center;
}

.progress-slider-container {
    flex: 1;
    height: 6px;
    background: rgba(255, 255, 255, 0.15);
    border-radius: var(--radius-full);
    position: relative;
    cursor: pointer;
}

/* Touch targeting pad expansion */
.progress-slider-container::before {
    content: "";
    position: absolute;
    top: -10px;
    bottom: -10px;
    left: 0;
    right: 0;
}

.progress-fill {
    height: 100%;
    background: var(--color-all);
    border-radius: var(--radius-full);
    width: 0%;
}

.progress-handle {
    width: 12px;
    height: 12px;
    background: #ffffff;
    border-radius: 50%;
    position: absolute;
    top: 50%;
    transform: translate(-50%, -50%);
    box-shadow: 0 0 10px rgba(63, 103, 198, 0.8);
    opacity: 1; /* Always visible to make scrubbing intuitive on both desktop and mobile */
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.progress-slider-container:hover .progress-handle {
    transform: translate(-50%, -50%) scale(1.25);
    box-shadow: 0 0 15px rgba(147, 197, 253, 1);
}


/* Volume Slider Controls */
.audio-volume-container {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    width: 18%;
    min-width: 120px;
    justify-content: flex-end;
}

.audio-volume-container i {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.audio-volume-container input[type="range"] {
    width: 60px;
    height: 3px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-full);
    outline: none;
    -webkit-appearance: none;
    cursor: pointer;
}

.audio-volume-container input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #ffffff;
}

.close-player-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 0.9rem;
    cursor: pointer;
    margin-left: 0.75rem;
    transition: color var(--transition-fast);
}

.close-player-btn:hover {
    color: #ef4444;
}

/* --- Responsive Layout Breakpoints --- */

@media (max-width: 1280px) {
    .audio-player-footer {
        left: calc(50% + 120px);
        width: calc(100% - 300px);
    }
}

@media (max-width: 1024px) {
    .sidebar {
        width: 80px;
        padding: 1.5rem 0.5rem;
    }
    
    .sidebar-brand {
        margin-bottom: 2rem;
    }
    
    .sidebar-brand img {
        content: url('../Logos/mind-yaro-favicon.png'); /* Swap for compact logo if user has favicon */
        max-width: 32px;
    }
    
    .course-selector-list li {
        justify-content: center;
        padding: 0.75rem;
    }
    
    .course-name {
        display: none;
    }
    
    .menu-section h3 {
        display: none;
    }
    
    .back-link {
        font-size: 1.1rem;
        justify-content: center;
    }
    
    .back-link span {
        display: none;
    }
    
    .main-content {
        margin-left: 80px;
        padding: 2rem;
    }
    
    .audio-player-footer {
        left: calc(50% + 40px);
        width: calc(100% - 120px);
    }
}

@media (max-width: 768px) {
    .app-container {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
        padding: 1rem;
        border-right: none;
        border-bottom: 1px solid var(--border-glass);
    }
    
    .sidebar-brand {
        margin-bottom: 1rem;
    }
    
    .sidebar-brand img {
        content: initial;
        max-height: 35px;
    }
    
    .course-selector-list {
        flex-direction: row;
        overflow-x: auto;
        padding-bottom: 0.5rem;
    }
    
    .course-selector-list li {
        flex-shrink: 0;
        padding: 0.5rem 0.75rem;
    }
    
    .course-name {
        display: inline;
        font-size: 0.75rem;
    }
    
    .main-content {
        margin-left: 0;
        padding: 1.5rem;
    }
    
    .dashboard-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .search-box {
        width: 100%;
    }
    
    .audio-player-footer {
        bottom: 0;
        left: 0;
        transform: translateY(100%);
        width: 100%;
        border-radius: 0;
        border-left: none;
        border-right: none;
        border-bottom: none;
        padding: 1rem;
        flex-direction: column;
        gap: 1rem;
    }
    
    .audio-player-footer.active {
        transform: translateY(0);
    }
    
    .audio-track-info {
        width: 100%;
    }
    
    .audio-controls-container {
        width: 100%;
    }
    
    .audio-volume-container {
        display: none;
    }
}