:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-accent: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #10b981;
    --accent-hover: #059669;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --card-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    overflow: hidden;
}

h1, h2, h3, .logo {
    font-family: 'Outfit', sans-serif;
}

.app-container {
    display: flex;
    height: 100vh;
    width: 100vw;
}

/* Sidebar Styles */
.sidebar {
    width: 350px;
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    z-index: 100;
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--glass-border);
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--accent-color);
    margin-bottom: 1.5rem;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
}

.search-box i {
    position: absolute;
    left: 1rem;
    color: var(--text-secondary);
}

.search-box input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.5rem;
    background-color: var(--bg-accent);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 0.9rem;
    outline: none;
    transition: border-color 0.2s;
}

.search-box input:focus {
    border-color: var(--accent-color);
}

.progress-section {
    padding: 1.5rem;
    background: linear-gradient(180deg, rgba(16, 185, 129, 0.05) 0%, transparent 100%);
}

.progress-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-size: 0.85rem;
    font-weight: 600;
}

.progress-bar {
    height: 8px;
    background-color: var(--bg-accent);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-bar-fill {
    height: 100%;
    background-color: var(--accent-color);
    width: 0%;
    transition: width 0.5s ease;
}

.progress-stats {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.chapters-list {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
}

.chapter {
    margin-bottom: 0.5rem;
}

.chapter-title {
    padding: 0.75rem 1rem;
    background-color: var(--bg-accent);
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 0.9rem;
    transition: background-color 0.2s;
}

.chapter-title:hover {
    background-color: rgba(255, 255, 255, 0.05);
}

.chapter i {
    transition: transform 0.3s;
}

.chapter.open i {
    transform: rotate(180deg);
}

.chapter-videos {
    display: none;
    padding: 0.5rem 0;
}

.chapter.open .chapter-videos {
    display: block;
}

.video-item {
    padding: 0.6rem 1rem 0.6rem 2rem;
    font-size: 0.85rem;
    cursor: pointer;
    border-radius: 6px;
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    transition: all 0.2s;
    color: var(--text-secondary);
}

.video-item:hover {
    background-color: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

.video-item.active {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--accent-color);
    font-weight: 600;
}

.video-item.completed .check-icon {
    color: var(--accent-color);
}

.sidebar-footer {
    padding: 1.5rem;
    border-top: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.footer-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.85rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: color 0.2s;
}

.footer-link:hover {
    color: var(--text-primary);
}

/* Main Content Styles */
.main-content {
    flex: 1;
    height: 100vh;
    overflow-y: auto;
    background-color: var(--bg-primary);
    display: flex;
    flex-direction: column;
}

.video-player-container {
    background-color: #000;
    position: sticky;
    top: 0;
    z-index: 50;
}

.video-aspect-ratio {
    width: 100%;
    aspect-ratio: 16 / 9;
    max-height: 70vh;
}

#player {
    width: 100%;
    height: 100%;
    border: none;
}

.video-info {
    padding: 1.5rem 2rem;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--glass-border);
}

.info-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.current-title {
    font-size: 1.25rem;
    font-weight: 700;
    max-width: 70%;
}

.btn {
    padding: 0.6rem 1.2rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    border: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.2s;
}

.btn-primary {
    background-color: var(--accent-color);
    color: #fff;
}

.btn-primary:hover {
    background-color: var(--accent-hover);
    transform: translateY(-1px);
}

.btn-success {
    background-color: transparent;
    border: 1px solid var(--accent-color);
    color: var(--accent-color);
}

/* Tabs */
.content-tabs {
    flex: 1;
    padding: 2rem;
}

.curriculum-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.tab-header {
    display: flex;
    gap: 2rem;
    border-bottom: 1px solid var(--glass-border);
    margin-bottom: 2rem;
}

.tab-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    padding: 0.75rem 0;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    position: relative;
}

.tab-btn.active {
    color: var(--text-primary);
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--accent-color);
}

.hidden {
    display: none;
}

/* Completion Tab */
.completion-card {
    background: var(--bg-secondary);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 2rem;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.celebration-header i {
    font-size: 3rem;
    color: #fbbf24;
    margin-bottom: 1rem;
}

.celebration-header h2 {
    margin-bottom: 0.5rem;
}

.celebration-header p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.completion-checklist {
    text-align: left;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1rem;
    margin-top: 2rem;
}

.checklist-item {
    background-color: var(--bg-accent);
    padding: 1rem;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 1rem;
    border: 1px solid transparent;
    transition: all 0.2s;
}

.checklist-item.done {
    border-color: var(--accent-color);
    background-color: rgba(16, 185, 129, 0.05);
}

.checklist-item i {
    font-size: 1.25rem;
    color: var(--text-secondary);
}

.checklist-item.done i {
    color: var(--accent-color);
}

/* Resources Tab */
.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1.5rem;
}

.resource-item {
    background: var(--bg-secondary);
    border: 1px solid var(--glass-border);
    padding: 1.5rem;
    border-radius: 12px;
    text-align: center;
    cursor: pointer;
    transition: transform 0.2s;
}

.resource-item:hover {
    transform: translateY(-5px);
    border-color: var(--accent-color);
}

.resource-item i {
    font-size: 2rem;
    margin-bottom: 1rem;
    display: block;
}

/* Mobile Responsive */
@media (max-width: 1024px) {
    .sidebar {
        width: 300px;
    }
}

@media (max-width: 768px) {
    .app-container {
        flex-direction: column;
    }
    .sidebar {
        width: 100%;
        height: auto;
        max-height: 400px;
    }
    .main-content {
        height: auto;
    }
}