:root {
    --sidebar-bg: #1a1a1a;
    --sidebar-text: #ffffff;
    --accent-orange: #FF6B35;
    --bg-body: #f5f7fa;
    --card-bg: #ffffff;
    --text-dark: #333333;
    --text-light: #666666;
    --sidebar-width: 12.5%;
    --success: #0F9D58;
    --danger: #DB4437;
    --warning: #F4B400;
    --info: #4285F4;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg-body);
    color: var(--text-dark);
}

/* Flash Messages */
.flash-messages {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
}

.alert {
    padding: 15px 20px;
    margin-bottom: 10px;
    border-radius: 5px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from { transform: translateX(400px); }
    to { transform: translateX(0); }
}

.alert-success { background: var(--success); color: white; }
.alert-error { background: var(--danger); color: white; }
.alert-warning { background: var(--warning); color: white; }
.alert-info { background: var(--info); color: white; }

/* Navbar */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 30px;
    background: var(--sidebar-bg);
    color: white;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar-brand a {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--accent-orange);
    text-decoration: none;
}

.navbar-brand a:hover {
    color: #ff8c61;
}

.navbar-links {
    display: flex;
    align-items: center;
    gap: 15px;
}

.navbar-user {
    color: #ccc;
    margin-right: 10px;
    font-size: 0.9rem;
}

/* App Container */
.app-container {
    display: flex;
    height: calc(100vh - 70px);
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--sidebar-bg);
    color: var(--sidebar-text);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    flex-shrink: 0;
}

.logo-area {
    padding: 20px;
    font-size: 1.5rem;
    font-weight: bold;
    border-bottom: 1px solid #333;
    color: var(--accent-orange);
}

.menu {
    list-style: none;
    padding: 10px 0;
    flex-grow: 1;
}

.course-item {
    border-bottom: 1px solid #333;
}

.course-title {
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.3s;
}

.course-title:hover {
    background-color: #333;
    color: var(--accent-orange);
}

.chevron {
    transition: transform 0.3s;
    font-size: 0.8rem;
}

.course-item.active .chevron {
    transform: rotate(90deg);
    color: var(--accent-orange);
}

.course-item.active .course-title {
    color: var(--accent-orange);
    background-color: #252525;
}

.modules-list {
    list-style: none;
    background-color: #252525;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-out;
}

.course-item.active .modules-list {
    max-height: 1000px;
}

.module-item {
    border-bottom: 1px solid #333;
}

.module-title {
    padding: 12px 20px 12px 35px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-size: 0.9rem;
    color: #ccc;
    transition: color 0.3s;
}

.module-title:hover {
    color: #fff;
}

.module-item.active .module-title {
    color: var(--accent-orange);
}

.module-item.active .chevron {
    transform: rotate(180deg);
}

.lessons-list {
    list-style: none;
    background-color: #1a1a1a;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-out;
}

.module-item.active .lessons-list {
    max-height: 1000px;
}

.lesson-item {
    padding: 10px 20px 10px 55px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.85rem;
    color: #aaa;
    cursor: pointer;
    transition: all 0.2s;
}

.lesson-item:hover {
    background-color: #333;
    color: #fff;
}

.lesson-icon {
    width: 20px;
    text-align: center;
}

.icon-video { color: var(--info); }
.icon-pdf { color: var(--danger); }
.icon-file { color: var(--warning); }

.lesson-duration {
    margin-left: auto;
    font-size: 0.75rem;
    color: #666;
}

.admin-link {
    padding: 20px;
    border-top: 1px solid #333;
}

.admin-link a {
    color: #999;
    text-decoration: none;
    transition: color 0.3s;
}

.admin-link a:hover {
    color: var(--accent-orange);
}

/* Main Content */
.main-content {
    flex-grow: 1;
    padding: 40px;
    overflow-y: auto;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid #e0e0e0;
}

.header h1 {
    font-size: 2rem;
    color: var(--text-dark);
}

.search-bar {
    padding: 12px 20px;
    border: 2px solid #ddd;
    border-radius: 25px;
    width: 350px;
    outline: none;
    font-size: 0.95rem;
    transition: border-color 0.3s;
}

.search-bar:focus {
    border-color: var(--accent-orange);
}

/* Welcome Card */
.welcome-card {
    background: linear-gradient(135deg, var(--accent-orange), #ff8c61);
    color: white;
    padding: 30px;
    border-radius: 10px;
    margin-bottom: 30px;
    box-shadow: 0 4px 15px rgba(255, 107, 53, 0.3);
}

.welcome-card h2 {
    margin-bottom: 10px;
}

.stats {
    display: flex;
    gap: 30px;
    margin-top: 20px;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: bold;
}

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

/* Cards Grid */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 25px;
}

.card {
    background: var(--card-bg);
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
    overflow: hidden;
    transition: all 0.3s;
    display: block;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.card-body {
    padding: 25px;
}

.card-icon {
    font-size: 3rem;
    margin-bottom: 15px;
    display: block;
}

.card-title {
    font-size: 1.2rem;
    font-weight: bold;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.card-desc {
    font-size: 0.95rem;
    color: var(--text-light);
    line-height: 1.5;
    margin-bottom: 15px;
}

.card-meta {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
    flex-wrap: wrap;
}

.badge {
    padding: 4px 10px;
    background: #f0f0f0;
    border-radius: 15px;
    font-size: 0.75rem;
    font-weight: 600;
}

.badge-video { background: #e3f2fd; color: var(--info); }
.badge-pdf { background: #ffebee; color: var(--danger); }
.badge-link { background: #fff3e0; color: var(--warning); }
.badge-file { background: #e8f5e9; color: var(--success); }

.progress-bar {
    height: 6px;
    background: #e0e0e0;
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--accent-orange);
    border-radius: 3px;
    transition: width 0.3s;
}

/* Buttons */
.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.95rem;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s;
    font-weight: 600;
}

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

.btn-primary:hover {
    background: #e55a2b;
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--info);
    color: white;
}

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

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

.btn-outline {
    background: transparent;
    border: 2px solid var(--accent-orange);
    color: var(--accent-orange);
}

.btn-outline:hover {
    background: var(--accent-orange);
    color: white;
}

.btn-link {
    background: transparent;
    color: var(--info);
    text-decoration: underline;
}

.btn-small {
    padding: 5px 12px;
    font-size: 0.85rem;
}

.btn-tiny {
    padding: 3px 8px;
    font-size: 0.8rem;
    background: none;
    border: none;
    cursor: pointer;
    opacity: 0.7;
    transition: opacity 0.3s;
}

.btn-tiny:hover {
    opacity: 1;
}

.btn-block {
    width: 100%;
    padding: 12px;
    font-size: 1rem;
}

/* Auth Pages */
.auth-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: calc(100vh - 70px);
    background: var(--bg-body);
    padding: 20px;
}

.auth-card {
    background: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    width: 100%;
    max-width: 400px;
}

.auth-card h1 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--text-dark);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
    color: var(--text-dark);
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid #ddd;
    border-radius: 5px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--accent-orange);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.auth-link {
    text-align: center;
    margin-top: 20px;
    color: var(--text-light);
}

.auth-link a {
    color: var(--accent-orange);
    text-decoration: none;
    font-weight: 600;
}

/* Dashboard */
.dashboard-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}

.dashboard-header {
    margin-bottom: 30px;
}

.dashboard-header h1 {
    margin-bottom: 10px;
}

.dashboard-subtitle {
    color: var(--text-light);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: white;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}

.stat-card h3 {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 10px;
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    color: var(--text-dark);
    margin-bottom: 15px;
}

.stat-percentage {
    text-align: center;
    margin-top: 10px;
    font-weight: bold;
    color: var(--accent-orange);
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-light);
}

.dashboard-actions {
    display: flex;
    gap: 15px;
    margin-bottom: 30px;
}

.dashboard-recent {
    background: white;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}

.dashboard-recent h2 {
    margin-bottom: 20px;
}

.activity-list {
    list-style: none;
}

.activity-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 10px 0;
    border-bottom: 1px solid #eee;
}

.activity-icon {
    color: var(--success);
    font-weight: bold;
}

.activity-text {
    flex: 1;
}

.activity-date {
    color: var(--text-light);
    font-size: 0.85rem;
}

.no-activity {
    color: var(--text-light);
    font-style: italic;
}

/* Lesson Viewer */
.lesson-viewer {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}

.lesson-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.lesson-header h1 {
    font-size: 2rem;
    color: var(--text-dark);
}

.video-container,
.pdf-container {
    background: #000;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 30px;
}

.lesson-info {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}

.lesson-info h3 {
    margin-bottom: 15px;
    color: var(--text-dark);
}

.lesson-info p {
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 20px;
}

.lesson-meta {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.pdf-actions {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
}

.lesson-navigation {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid #eee;
}

/* Admin Panel */
.admin-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 30px;
}

.admin-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid #e0e0e0;
}

.admin-header h1 {
    font-size: 2rem;
}

.admin-grid {
    display: grid;
    gap: 30px;
}

.admin-section {
    background: white;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.admin-section h2 {
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--accent-orange);
}

.form-card {
    background: #f9f9f9;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.form-card h3 {
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.inline-form {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    align-items: center;
}

.inline-form input,
.inline-form select {
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 0.9rem;
}

.inline-form input[type="text"] {
    flex: 1;
    min-width: 150px;
}

.inline-form input[type="number"] {
    width: 80px;
}

.list-container {
    margin-top: 20px;
}

.list-item {
    background: #fafafa;
    padding: 15px;
    margin-bottom: 10px;
    border-radius: 5px;
    border-left: 4px solid var(--accent-orange);
}

.list-item-content {
    display: flex;
    flex-direction: column;
    gap: 5px;
}

.list-item-content strong {
    font-size: 1.1rem;
}

.list-item-content small {
    color: var(--text-light);
}

.list-item-actions {
    margin-top: 10px;
    display: flex;
    gap: 10px;
}

.edit-form {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #ddd;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.edit-form input,
.edit-form select {
    padding: 8px;
    border: 1px solid #ddd;
    border-radius: 5px;
}

.nested-section {
    margin-top: 15px;
    margin-left: 20px;
    padding-left: 15px;
    border-left: 2px solid #e0e0e0;
}

.nested-section h4 {
    margin-bottom: 10px;
    color: var(--text-light);
    font-size: 0.95rem;
}

.nested-item {
    background: white;
    padding: 12px;
    margin-bottom: 8px;
    border-radius: 5px;
    border: 1px solid #e0e0e0;
}

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

.nested-item-header span {
    font-weight: 600;
}

.lessons-section {
    margin-top: 10px;
    margin-left: 15px;
    padding-left: 10px;
    border-left: 2px solid #f0f0f0;
}

.lessons-section h5 {
    margin-bottom: 10px;
    font-size: 0.9rem;
    color: #999;
}

.lesson-item-admin {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px;
    background: #f9f9f9;
    margin-bottom: 5px;
    border-radius: 4px;
    font-size: 0.9rem;
}

.lesson-item-admin .badge {
    font-size: 0.7rem;
}

.lesson-item-admin strong {
    flex: 1;
}

.lesson-item-admin small {
    color: #999;
    margin-right: 10px;
}

.lesson-item-admin .actions {
    display: flex;
    gap: 5px;
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        height: auto;
    }
    
    .app-container {
        flex-direction: column;
    }
    
    .main-content {
        padding: 20px;
    }
    
    .header {
        flex-direction: column;
        gap: 15px;
        align-items: stretch;
    }
    
    .search-bar {
        width: 100%;
    }
    
    .inline-form {
        flex-direction: column;
    }
    
    .inline-form input[type="text"] {
        width: 100%;
    }
    
    .navbar {
        flex-direction: column;
        gap: 10px;
        padding: 15px;
    }
    
    .navbar-links {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .stats {
        flex-direction: column;
        gap: 15px;
    }
    
    .dashboard-actions {
        flex-direction: column;
    }
    
    .pdf-actions {
        flex-direction: column;
    }
}