:root {
    --primary-blue: #0d6efd;
    --secondary-blue: #0b5ed7;
    --light-bg: #f8f9fa;
    --note-color: #198754;
    
    /* Light mode colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --border-color: #dee2e6;
    --card-bg: #ffffff;
    --navbar-bg: #ffffff;
    --footer-bg: #ffffff;
}

/* Dark mode colors */
[data-theme="dark"] {
    --primary-blue: #4a9eff;
    --note-color: #28a745;
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --text-primary: #e9ecef;
    --text-secondary: #adb5bd;
    --border-color: #495057;
    --card-bg: #2d2d2d;
    --navbar-bg: #212529;
    --footer-bg: #212529;
    --light-bg: #1a1a1a;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Navbar */
.navbar {
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    background-color: var(--navbar-bg) !important;
    transition: background-color 0.3s ease;
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--primary-blue) !important;
}

.nav-link {
    color: var(--text-primary) !important;
    transition: color 0.3s ease;
}

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

/* Dark Mode Toggle Button */
.theme-toggle {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-left: 1rem;
}

.theme-toggle:hover {
    background-color: var(--bg-secondary);
    border-color: var(--primary-blue);
}

.theme-toggle i {
    font-size: 1.2rem;
}

/* Cards */
.card {
    background-color: var(--card-bg);
    border-color: var(--border-color);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.hover-card {
    cursor: pointer;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
}

.hover-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.3) !important;
}

[data-theme="dark"] .hover-card:hover {
    box-shadow: 0 0.5rem 1rem rgba(255, 255, 255, 0.1) !important;
}

.grade-icon {
    font-size: 3.5rem;
    margin-bottom: 1rem;
}

.subject-icon {
    color: var(--primary-blue);
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.subject-icon.notes {
    color: var(--note-color);
}

.paper-card {
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
}

.paper-card.note-card {
    border-left: 4px solid var(--note-color);
}

/* Badges */
.badge-year {
    background-color: var(--primary-blue);
    font-size: 0.9rem;
}

.badge-term {
    background-color: #6c757d;
    font-size: 0.9rem;
}

.badge-note {
    background-color: var(--note-color);
    font-size: 0.9rem;
}

/* Footer */
footer {
    background-color: var(--footer-bg);
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    transition: all 0.3s ease;
}

.page-title {
    color: var(--primary-blue);
    font-weight: 700;
}

/* Breadcrumb */
.breadcrumb {
    background: transparent;
    padding: 0;
    margin-bottom: 1.5rem;
}

.breadcrumb-item a {
    color: var(--primary-blue);
    text-decoration: none;
}

.breadcrumb-item.active {
    color: var(--text-secondary);
}

/* Hero Section */
.hero-section {
    padding: 3rem 0;
    text-align: center;
}

.hero-icon {
    font-size: 3rem;
    color: var(--primary-blue);
    margin-bottom: 1rem;
}

/* Search Box */
.search-box {
    max-width: 400px;
}

.search-box .form-control {
    background-color: var(--bg-secondary);
    border-color: var(--border-color);
    color: var(--text-primary);
}

.search-box .form-control:focus {
    background-color: var(--bg-secondary);
    border-color: var(--primary-blue);
    color: var(--text-primary);
}

.search-box .form-control::placeholder {
    color: var(--text-secondary);
}

/* Type Selector */
.type-selector {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.type-btn {
    padding: 1.5rem 2.5rem;
    border: 2px solid var(--border-color);
    border-radius: 0.5rem;
    background: var(--card-bg);
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
    min-width: 180px;
}

.type-btn:hover {
    transform: translateY(-5px);
    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
}

[data-theme="dark"] .type-btn:hover {
    box-shadow: 0 0.5rem 1rem rgba(255, 255, 255, 0.1);
}

.type-btn.papers:hover {
    border-color: var(--primary-blue);
    background-color: rgba(13, 110, 253, 0.1);
}

[data-theme="dark"] .type-btn.papers:hover {
    background-color: rgba(74, 158, 255, 0.2);
}

.type-btn.notes:hover {
    border-color: var(--note-color);
    background-color: rgba(25, 135, 84, 0.1);
}

[data-theme="dark"] .type-btn.notes:hover {
    background-color: rgba(40, 167, 69, 0.2);
}

.type-btn i {
    font-size: 3rem;
    display: block;
    margin-bottom: 1rem;
}

.type-btn.papers i {
    color: var(--primary-blue);
}

.type-btn.notes i {
    color: var(--note-color);
}

.type-btn h5 {
    margin-bottom: 0.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.type-btn small {
    color: var(--text-secondary);
}

/* Forms */
.form-control, .form-select {
    background-color: var(--bg-secondary);
    border-color: var(--border-color);
    color: var(--text-primary);
}

.form-control:focus, .form-select:focus {
    background-color: var(--bg-secondary);
    border-color: var(--primary-blue);
    color: var(--text-primary);
}

/* Alerts */
.alert-info {
    background-color: rgba(13, 110, 253, 0.1);
    border-color: var(--primary-blue);
    color: var(--text-primary);
}

[data-theme="dark"] .alert-info {
    background-color: rgba(74, 158, 255, 0.2);
}

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

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

.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);
    color: white;
}

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

/* Text colors */
.text-muted {
    color: var(--text-secondary) !important;
}

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

/* Responsive adjustments */
@media (max-width: 768px) {
    .type-btn {
        min-width: 150px;
        padding: 1.2rem 1.8rem;
    }
    
    .type-btn i {
        font-size: 2.5rem;
    }
    
    .hero-section {
        padding: 2rem 0;
    }
    
    .grade-icon {
        font-size: 2.5rem;
    }
    
    .theme-toggle {
        margin-left: 0;
        margin-top: 0.5rem;
        width: 100%;
    }
}

/* About page specific styles */
.about-card {
    transition: transform 0.3s ease;
}

.about-card:hover {
    transform: translateY(-3px);
}

/* Dark mode specific adjustments */
[data-theme="dark"] .bg-white {
    background-color: var(--bg-primary) !important;
}

[data-theme="dark"] .bg-light {
    background-color: var(--bg-secondary) !important;
}

[data-theme="dark"] .border {
    border-color: var(--border-color) !important;
}

[data-theme="dark"] .shadow-sm {
    box-shadow: 0 0.125rem 0.25rem rgba(255, 255, 255, 0.075) !important;
}

/* Smooth transitions for theme switching */
* {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}