:root {
    --primary-blue: #007bff;
    --secondary-blue: #0056b3;
    --light-blue: #e3f2fd;
    --accent-blue: #17a2b8;
    --dark-blue: #0056b3;
    --light-gray: #f8f9fa;
}

/* General Styles */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f8f9fa;
}

/* Navigation */
.navbar {
    background: white !important;
    box-shadow: 0 2px 10px rgba(0, 123, 255, 0.1);
}

.navbar-brand {
    color: var(--primary-blue) !important;
    font-weight: bold;
    font-size: 1.5rem;
}

.nav-link {
    color: #495057 !important;
    font-weight: 500;
    transition: color 0.3s;
}

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

.nav-link.active {
    color: var(--primary-blue) !important;
    border-bottom: 2px solid var(--primary-blue);
}

/* Buttons */
.btn-primary {
    background-color: var(--primary-blue);
    border-color: var(--primary-blue);
    transition: all 0.3s;
}

.btn-primary:hover {
    background-color: var(--secondary-blue);
    border-color: var(--secondary-blue);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 123, 255, 0.3);
}

.btn-outline-primary {
    color: var(--primary-blue);
    border-color: var(--primary-blue);
}

.btn-outline-primary:hover {
    background-color: var(--primary-blue);
    border-color: var(--primary-blue);
}

/* Cards */
.card {
    border: none;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 123, 255, 0.15);
}

.card-header {
    background-color: var(--primary-blue);
    color: white;
    border-radius: 10px 10px 0 0 !important;
    padding: 15px 20px;
}

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

/* Badges */
.badge {
    font-weight: 500;
    padding: 5px 10px;
    border-radius: 20px;
}

.bg-primary {
    background-color: var(--primary-blue) !important;
}

/* Progress Bars */
.progress {
    border-radius: 10px;
}

.progress-bar {
    background-color: var(--primary-blue);
    border-radius: 10px;
}

/* Tables */
.table {
    --bs-table-hover-bg: var(--light-blue);
}

.table th {
    background-color: var(--light-blue);
    border-color: #dee2e6;
    color: var(--dark-blue);
}

/* Alerts */
.alert {
    border: none;
    border-radius: 10px;
}

.alert-primary {
    background-color: var(--light-blue);
    color: var(--dark-blue);
    border-left: 4px solid var(--primary-blue);
}

/* Pagination */
.page-link {
    color: var(--primary-blue);
}

.page-item.active .page-link {
    background-color: var(--primary-blue);
    border-color: var(--primary-blue);
}

/* Footer */
.footer {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--accent-blue) 100%);
    color: white;
    margin-top: 50px;
}

.footer a {
    color: white;
    text-decoration: none;
    transition: opacity 0.3s;
}

.footer a:hover {
    opacity: 0.8;
}

/* Course Cards */
.course-card {
    height: 100%;
    display: flex;
    flex-direction: column;
}

.course-card .card-body {
    flex: 1;
}

.course-card .card-footer {
    background: transparent;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
}

/* Hero Sections */
.hero-section {
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(0, 123, 255, 0.9) 0%, rgba(23, 162, 184, 0.9) 100%);
    z-index: 1;
}

.hero-section > * {
    position: relative;
    z-index: 2;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-section {
        padding: 60px 0 !important;
    }
    
    .display-4 {
        font-size: 2.5rem;
    }
    
    .card {
        margin-bottom: 20px;
    }
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.5s ease-out;
}

/* Loading Spinner */
.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--light-blue);
    border-top: 4px solid var(--primary-blue);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Tooltips */
.tooltip-inner {
    background-color: var(--primary-blue);
    border-radius: 5px;
    padding: 5px 10px;
}

.tooltip.bs-tooltip-top .tooltip-arrow::before {
    border-top-color: var(--primary-blue);
}

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

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

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

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-blue);
}