:root {
    --primary-blue: #000080;
    --primary-blue-light: #1a1aff;
    --success-green: #28a745;
    --success-green-light: #34d058;
    --gray-neutral: #6c757d;
    --gray-light: #f8f9fa;
    --gray-dark: #343a40;
    --white: #ffffff;
    --black: #000000;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.2);
    --border-radius: 12px;
    --border-radius-sm: 8px;
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --gray-light: #1a1a1a;
    --gray-dark: #e9ecef;
    --white: #2d2d2d;
    --black: #f8f9fa;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--black);
    background-color: var(--gray-light);
}

.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary-blue);
    color: white;
    padding: 8px;
    text-decoration: none;
    z-index: 100;
}

.skip-link:focus {
    top: 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.hero-section {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--primary-blue-light) 100%);
    color: white;
    padding: 80px 0 60px;
    text-align: center;
}

.hero-section h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.hero-subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: 32px;
}

.progress-container {
    max-width: 600px;
    margin: 0 auto;
}

.progress-bar {
    width: 100%;
    height: 12px;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 6px;
    overflow: hidden;
    margin-bottom: 12px;
}

.progress-fill {
    height: 100%;
    background: var(--success-green-light);
    border-radius: 6px;
    transition: width 0.5s ease;
    width: 0%;
}

.progress-text {
    font-size: 0.95rem;
    opacity: 0.9;
}

.modules-section {
    padding: 60px 0;
}

.module {
    margin-bottom: 60px;
}

.module-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-blue);
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 3px solid var(--primary-blue);
}

[data-theme="dark"] .module-title {
    color: var(--primary-blue-light);
    border-bottom-color: var(--primary-blue-light);
}

.lesson-card {
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    overflow: hidden;
    transition: var(--transition);
}

.lesson-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.lesson-card.completed {
    border-left: 4px solid var(--success-green);
}

.lesson-header {
    display: flex;
    align-items: center;
    padding: 20px 24px;
    gap: 16px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] .lesson-header {
    border-bottom-color: rgba(255, 255, 255, 0.1);
}

.lesson-number {
    width: 40px;
    height: 40px;
    background: var(--primary-blue);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.lesson-card.completed .lesson-number {
    background: var(--success-green);
}

.lesson-title {
    flex: 1;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--black);
}

.btn-complete {
    width: 44px;
    height: 44px;
    border: 2px solid var(--gray-neutral);
    background: transparent;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    flex-shrink: 0;
}

.btn-complete:hover {
    border-color: var(--success-green);
    background: rgba(40, 167, 69, 0.1);
}

.btn-complete:focus {
    outline: 3px solid var(--primary-blue-light);
    outline-offset: 2px;
}

.check-icon {
    width: 20px;
    height: 20px;
    stroke: var(--gray-neutral);
    opacity: 0;
    transition: var(--transition);
}

.lesson-card.completed .btn-complete {
    border-color: var(--success-green);
    background: var(--success-green);
}

.lesson-card.completed .check-icon {
    stroke: white;
    opacity: 1;
}

.lesson-description {
    padding: 0 24px;
    color: var(--gray-neutral);
    font-size: 0.95rem;
    margin-top: -8px;
}

.lesson-video {
    padding: 20px 24px;
}

.video-placeholder {
    width: 100%;
    max-width: 640px;
    margin: 0 auto;
    aspect-ratio: 16 / 9;
    border-radius: var(--border-radius-sm);
    background: linear-gradient(135deg, rgba(0, 0, 0, 0.08) 0%, rgba(0, 0, 0, 0.15) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--gray-dark);
    font-weight: 600;
    font-size: 1.05rem;
    letter-spacing: 0.2px;
}

[data-theme="dark"] .video-placeholder {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.06) 0%, rgba(255, 255, 255, 0.12) 100%);
    color: var(--gray-dark);
}

.video-thumbnail {
    position: relative;
    width: 100%;
    max-width: 640px;
    margin: 0 auto;
    aspect-ratio: 16 / 9;
    border-radius: var(--border-radius-sm);
    overflow: hidden;
    cursor: pointer;
    background: #000;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.video-thumbnail:hover img {
    transform: scale(1.05);
}

.play-overlay {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    transition: var(--transition);
}

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

.lesson-content {
    padding: 24px;
    background: var(--gray-light);
}

[data-theme="dark"] .lesson-content {
    background: rgba(0, 0, 0, 0.2);
}

.bible-reading,
.reflection-questions {
    margin-bottom: 24px;
}

.bible-reading:last-child,
.reflection-questions:last-child {
    margin-bottom: 0;
}

.bible-reading h4,
.reflection-questions h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--black);
}

.bible-reading ul,
.reflection-questions ol {
    padding-left: 24px;
}

.bible-reading li,
.reflection-questions li {
    margin-bottom: 8px;
    line-height: 1.6;
}

.bible-reading strong {
    color: var(--primary-blue);
}

[data-theme="dark"] .bible-reading strong {
    color: var(--primary-blue-light);
}

.completion-section {
    padding: 60px 0;
    background: linear-gradient(135deg, var(--success-green) 0%, var(--success-green-light) 100%);
    color: white;
    text-align: center;
}

.completion-card {
    max-width: 600px;
    margin: 0 auto;
    padding: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
    backdrop-filter: blur(10px);
}

.completion-card h2 {
    font-size: 2rem;
    margin-bottom: 16px;
}

.completion-card p {
    font-size: 1.1rem;
    margin-bottom: 16px;
    opacity: 0.95;
}

.btn {
    display: inline-block;
    padding: 12px 32px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: white;
    color: var(--primary-blue);
}

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

.video-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
}

.modal-content {
    position: relative;
    width: 90%;
    max-width: 900px;
    aspect-ratio: 16 / 9;
    background: #000;
    border-radius: var(--border-radius);
    overflow: hidden;
}

.modal-close {
    position: absolute;
    top: -40px;
    right: 0;
    background: transparent;
    border: none;
    color: white;
    font-size: 2rem;
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.modal-close:hover {
    transform: scale(1.2);
}

.modal-close:focus {
    outline: 3px solid white;
    outline-offset: 2px;
}

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

.video-container iframe {
    width: 100%;
    height: 100%;
    border: none;
}

@media (max-width: 768px) {
    .hero-section {
        padding: 60px 0 40px;
    }
    
    .hero-section h1 {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .module-title {
        font-size: 1.5rem;
    }
    
    .lesson-header {
        padding: 16px;
        flex-wrap: wrap;
    }
    
    .lesson-number {
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }
    
    .lesson-title {
        font-size: 1.1rem;
    }
    
    .lesson-content {
        padding: 16px;
    }
    
    .bible-reading h4,
    .reflection-questions h4 {
        font-size: 1rem;
    }
    
    .modal-content {
        width: 95%;
    }
    
    .modal-close {
        top: -36px;
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .hero-section h1 {
        font-size: 1.5rem;
    }
    
    .lesson-header {
        gap: 12px;
    }
    
    .btn-complete {
        width: 40px;
        height: 40px;
    }
    
    .check-icon {
        width: 18px;
        height: 18px;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        animation: none !important;
        transition: none !important;
    }
}

.reveal {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}