/* Coursera-Inspired Design System */

/* Root Variables */
:root {
    --primary: #0056D2;
    --primary-dark: #0044A8;
    --primary-light: #E8F0FE;
    --secondary: #1F1F1F;
    --accent: #E53935;
    --success: #2E7D32;
    --warning: #F9A825;
    --gray-50: #FAFAFA;
    --gray-100: #F5F5F5;
    --gray-200: #EEEEEE;
    --gray-300: #E0E0E0;
    --gray-400: #BDBDBD;
    --gray-500: #9E9E9E;
    --gray-600: #757575;
    --gray-700: #616161;
    --gray-800: #424242;
    --gray-900: #1F1F1F;
    --white: #FFFFFF;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--gray-50);
    color: var(--gray-900);
    line-height: 1.6;
}

/* Main Container */
.gradio-container {
    max-width: 1400px !important;
    margin: 0 auto;
    padding: 0 !important;
    background: var(--gray-50) !important;
}

/* Hero Section */
.hero-section {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: var(--white);
    padding: 48px 32px;
    margin-bottom: 32px;
    border-radius: 0;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 16px;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    opacity: 0.95;
    margin-bottom: 24px;
    max-width: 700px;
}

/* Stats Cards */
.stats-container {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    margin-top: 32px;
}

.stat-card {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    padding: 20px 24px;
    text-align: center;
    min-width: 120px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 4px;
}

.stat-label {
    font-size: 0.875rem;
    opacity: 0.9;
}

/* Course Card */
.course-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: all 0.3s ease;
    border: 1px solid var(--gray-200);
}

.course-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.course-card-header {
    padding: 24px;
    border-bottom: 1px solid var(--gray-200);
}

.course-card-body {
    padding: 24px;
}

.course-card-footer {
    padding: 16px 24px;
    background: var(--gray-50);
    border-top: 1px solid var(--gray-200);
}

/* Module Card */
.module-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    margin-bottom: 16px;
    overflow: hidden;
    border: 1px solid var(--gray-200);
    transition: all 0.3s ease;
}

.module-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--primary);
}

.module-header {
    padding: 20px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
    background: var(--white);
}

.module-header:hover {
    background: var(--gray-50);
}

.module-number {
    width: 40px;
    height: 40px;
    background: var(--primary);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.125rem;
    flex-shrink: 0;
}

.module-info {
    flex: 1;
    margin-left: 16px;
}

.module-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 4px;
}

.module-meta {
    font-size: 0.875rem;
    color: var(--gray-600);
}

.module-progress {
    display: flex;
    align-items: center;
    gap: 12px;
}

.progress-circle {
    width: 48px;
    height: 48px;
    position: relative;
}

.progress-bar-container {
    width: 100px;
    height: 6px;
    background: var(--gray-200);
    border-radius: 3px;
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: 3px;
    transition: width 0.5s ease;
}

/* Lesson Item */
.lesson-item {
    padding: 16px 24px;
    border-bottom: 1px solid var(--gray-100);
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: background 0.2s ease;
}

.lesson-item:hover {
    background: var(--gray-50);
}

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

.lesson-info {
    display: flex;
    align-items: center;
    gap: 12px;
    flex: 1;
}

.lesson-icon {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
}

.lesson-icon.video {
    background: #E3F2FD;
    color: #1565C0;
}

.lesson-icon.reading {
    background: #E8F5E9;
    color: #2E7D32;
}

.lesson-icon.quiz {
    background: #FFF3E0;
    color: #EF6C00;
}

.lesson-icon.assignment {
    background: #FCE4EC;
    color: #C2185B;
}

.lesson-status {
    display: flex;
    align-items: center;
    gap: 8px;
}

.status-badge {
    padding: 4px 12px;
    border-radius: 16px;
    font-size: 0.75rem;
    font-weight: 600;
}

.status-badge.completed {
    background: #E8F5E9;
    color: #2E7D32;
}

.status-badge.in-progress {
    background: #FFF3E0;
    color: #EF6C00;
}

.status-badge.not-started {
    background: var(--gray-100);
    color: var(--gray-600);
}

/* Quiz Styles */
.quiz-container {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    padding: 32px;
    margin: 24px 0;
}

.quiz-question {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 2px solid var(--gray-200);
}

.quiz-option {
    display: flex;
    align-items: center;
    padding: 16px 20px;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius);
    margin-bottom: 12px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.quiz-option:hover {
    border-color: var(--primary);
    background: var(--primary-light);
}

.quiz-option.selected {
    border-color: var(--primary);
    background: var(--primary-light);
}

.quiz-option.correct {
    border-color: var(--success);
    background: #E8F5E9;
}

.quiz-option.incorrect {
    border-color: var(--accent);
    background: #FFEBEE;
}

/* Buttons */
.btn-primary {
    background: var(--primary) !important;
    color: var(--white) !important;
    border: none !important;
    padding: 12px 24px !important;
    border-radius: var(--radius) !important;
    font-weight: 600 !important;
    font-size: 1rem !important;
    cursor: pointer !important;
    transition: all 0.2s ease !important;
}

.btn-primary:hover {
    background: var(--primary-dark) !important;
    transform: translateY(-2px) !important;
    box-shadow: var(--shadow-md) !important;
}

.btn-secondary {
    background: var(--white) !important;
    color: var(--primary) !important;
    border: 2px solid var(--primary) !important;
    padding: 10px 22px !important;
    border-radius: var(--radius) !important;
    font-weight: 600 !important;
    cursor: pointer !important;
    transition: all 0.2s ease !important;
}

.btn-secondary:hover {
    background: var(--primary-light) !important;
}

/* Progress Ring */
.progress-ring {
    width: 120px;
    height: 120px;
    position: relative;
}

.progress-ring-circle {
    transform: rotate(-90deg);
}

.progress-ring-bg {
    fill: none;
    stroke: var(--gray-200);
    stroke-width: 8;
}

.progress-ring-fill {
    fill: none;
    stroke: var(--primary);
    stroke-width: 8;
    stroke-linecap: round;
    transition: stroke-dashoffset 0.5s ease;
}

.progress-ring-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}

.progress-ring-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--gray-900);
}

.progress-ring-label {
    font-size: 0.75rem;
    color: var(--gray-600);
}

/* Sidebar */
.sidebar {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    padding: 24px;
    position: sticky;
    top: 24px;
}

.sidebar-section {
    margin-bottom: 24px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--gray-200);
}

.sidebar-section:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.sidebar-title {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--gray-600);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 16px;
}

/* Instructor Card */
.instructor-card {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px;
    background: var(--gray-50);
    border-radius: var(--radius);
    margin-bottom: 12px;
}

.instructor-avatar {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-weight: 700;
    font-size: 1.25rem;
}

.instructor-name {
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 4px;
}

.instructor-role {
    font-size: 0.875rem;
    color: var(--gray-600);
}

/* Tags */
.tag {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 16px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-right: 8px;
    margin-bottom: 8px;
}

.tag-beginner {
    background: #E8F5E9;
    color: #2E7D32;
}

.tag-intermediate {
    background: #FFF3E0;
    color: #EF6C00;
}

.tag-advanced {
    background: #FCE4EC;
    color: #C2185B;
}

/* Accordion */
.accordion {
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin-bottom: 16px;
}

.accordion-header {
    padding: 16px 20px;
    background: var(--white);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-weight: 600;
    transition: background 0.2s ease;
}

.accordion-header:hover {
    background: var(--gray-50);
}

.accordion-content {
    padding: 0 20px 20px;
    background: var(--white);
}

/* Rating Stars */
.rating {
    display: flex;
    align-items: center;
    gap: 4px;
}

.rating-star {
    color: #FFC107;
    font-size: 1rem;
}

.rating-star.empty {
    color: var(--gray-300);
}

.rating-number {
    font-weight: 600;
    margin-left: 8px;
    color: var(--gray-900);
}

.rating-count {
    color: var(--gray-600);
    font-size: 0.875rem;
    margin-left: 4px;
}

/* Video Player Placeholder */
.video-placeholder {
    background: linear-gradient(135deg, var(--gray-800) 0%, var(--gray-900) 100%);
    border-radius: var(--radius-lg);
    aspect-ratio: 16 / 9;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    position: relative;
    overflow: hidden;
}

.video-play-button {
    width: 80px;
    height: 80px;
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.video-play-button:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.1);
}

/* Certificate Preview */
.certificate-preview {
    background: linear-gradient(135deg, #FFD700 0%, #FFA500 100%);
    border-radius: var(--radius-lg);
    padding: 32px;
    text-align: center;
    color: var(--gray-900);
}

.certificate-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.certificate-subtitle {
    font-size: 1rem;
    opacity: 0.9;
}

/* Responsive */
@media (max-width: 768px