/* E-Learning System Styles */
:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --white-color: #ffffff;
    --gray-100: #f8f9fa;
    --gray-200: #e9ecef;
    --gray-300: #dee2e6;
    --gray-400: #ced4da;
    --gray-500: #adb5bd;
    --gray-600: #6c757d;
    --gray-700: #495057;
    --gray-800: #343a40;
    --gray-900: #212529;
}

/* Global Styles */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--gray-800);
    background-color: var(--white-color);
}

.bg-gradient-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, #0056b3 100%);
}

/* Navigation */
.navbar-brand {
    font-weight: 700;
    font-size: 1.5rem;
}

.navbar-nav .nav-link {
    font-weight: 500;
    padding: 0.75rem 1rem;
    transition: color 0.3s ease;
}

.navbar-nav .nav-link:hover {
    color: var(--primary-color) !important;
}

/* Hero Section */
.hero-section {
    min-height: 70vh;
    display: flex;
    align-items: center;
}

.hero-image i {
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* Feature Icons */
.feature-icon {
    width: 80px;
    height: 80px;
    font-size: 2rem;
}

/* Course Cards */
.course-card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border-radius: 15px;
    overflow: hidden;
}

.course-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1) !important;
}

.course-card .card-img-top {
    height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.course-card .card-body {
    padding: 1.5rem;
}

.course-card .card-footer {
    padding: 1rem 1.5rem;
}

/* Buttons */
.btn {
    border-radius: 8px;
    font-weight: 500;
    padding: 0.75rem 1.5rem;
    transition: all 0.3s ease;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

/* Cards */
.card {
    border-radius: 15px;
    border: none;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
}

.card:hover {
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

/* Progress Bars */
.progress {
    height: 8px;
    border-radius: 10px;
    background-color: var(--gray-200);
}

.progress-bar {
    border-radius: 10px;
    background: linear-gradient(90deg, var(--primary-color), #0056b3);
}

/* Video Player */
.video-container {
    position: relative;
    width: 100%;
    height: 0;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    background-color: var(--gray-900);
    border-radius: 15px;
    overflow: hidden;
}

.video-container iframe,
.video-container video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* Lesson List */
.lesson-item {
    padding: 1rem;
    border: 1px solid var(--gray-200);
    border-radius: 10px;
    margin-bottom: 0.5rem;
    transition: all 0.3s ease;
    cursor: pointer;
}

.lesson-item:hover {
    background-color: var(--gray-100);
    border-color: var(--primary-color);
}

.lesson-item.completed {
    background-color: #d4edda;
    border-color: var(--success-color);
}

.lesson-item.current {
    background-color: #cce5ff;
    border-color: var(--primary-color);
}

/* Dashboard */
.dashboard-card {
    background: linear-gradient(135deg, var(--primary-color), #0056b3);
    color: white;
    border-radius: 15px;
    padding: 2rem;
    margin-bottom: 2rem;
}

.dashboard-card h3 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.dashboard-card p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Stats Cards */
.stats-card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    text-align: center;
    transition: transform 0.3s ease;
}

.stats-card:hover {
    transform: translateY(-5px);
}

.stats-card .icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    font-size: 1.5rem;
}

.stats-card .number {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

/* Forms */
.form-control {
    border-radius: 10px;
    border: 2px solid var(--gray-300);
    padding: 0.75rem 1rem;
    transition: all 0.3s ease;
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
}

.form-label {
    font-weight: 600;
    color: var(--gray-700);
    margin-bottom: 0.5rem;
}

/* Alerts */
.alert {
    border-radius: 10px;
    border: none;
    padding: 1rem 1.5rem;
    margin-bottom: 1.5rem;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
}

.alert-danger {
    background-color: #f8d7da;
    color: #721c24;
}

.alert-info {
    background-color: #d1ecf1;
    color: #0c5460;
}

.alert-warning {
    background-color: #fff3cd;
    color: #856404;
}

/* Sidebar */
.sidebar {
    background-color: var(--gray-100);
    min-height: 100vh;
    padding: 2rem 0;
}

.sidebar .nav-link {
    color: var(--gray-700);
    padding: 0.75rem 1.5rem;
    border-radius: 10px;
    margin-bottom: 0.5rem;
    transition: all 0.3s ease;
}

.sidebar .nav-link:hover,
.sidebar .nav-link.active {
    background-color: var(--primary-color);
    color: white;
}

/* Footer */
footer {
    background-color: var(--gray-900) !important;
}

footer h5 {
    color: var(--white-color);
    margin-bottom: 1rem;
}

footer p {
    color: var(--gray-400);
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-section {
        min-height: 50vh;
        text-align: center;
    }
    
    .hero-section h1 {
        font-size: 2.5rem;
    }
    
    .dashboard-card h3 {
        font-size: 2rem;
    }
    
    .stats-card .number {
        font-size: 1.5rem;
    }
}

@media (max-width: 576px) {
    .hero-section h1 {
        font-size: 2rem;
    }
    
    .btn-lg {
        padding: 0.75rem 1.5rem;
        font-size: 1rem;
    }
    
    .course-card .card-body {
        padding: 1rem;
    }
}

/* Loading Animation */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--gray-200);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #0056b3;
}

/* Utility Classes */
.text-gradient {
    background: linear-gradient(135deg, var(--primary-color), #0056b3);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.shadow-soft {
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08) !important;
}

.shadow-strong {
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15) !important;
}

.border-radius-lg {
    border-radius: 15px !important;
}

.border-radius-xl {
    border-radius: 20px !important;
}