/* Main Styles for Your Reference Book */

:root {
    --primary-blue: #0066cc;
    --primary-blue-dark: #004d99;
    --light-blue: #e6f2ff;
    --dark-blue: #003366;
    --text-dark: #333333;
    --text-muted: #6c757d;
    --border-color: #dee2e6;
}

/* Global Styles */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-dark);
    line-height: 1.7;
}

a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: var(--primary-blue-dark);
    text-decoration: none;
}

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

.navbar-light .navbar-nav .nav-link {
    color: var(--text-dark);
    font-weight: 500;
    padding: 0.5rem 1rem;
    transition: color 0.3s ease;
}

.navbar-light .navbar-nav .nav-link:hover,
.navbar-light .navbar-nav .nav-link.active {
    color: var(--primary-blue);
}

/* Hero Section */
.hero-section {
    background: linear-gradient(135deg, var(--light-blue) 0%, #ffffff 100%);
    padding: 4rem 0;
}

.min-vh-60 {
    min-height: 60vh;
}

/* Buttons */
.btn-primary {
    background-color: var(--primary-blue);
    border-color: var(--primary-blue);
    padding: 0.75rem 2rem;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-primary:hover {
    background-color: var(--primary-blue-dark);
    border-color: var(--primary-blue-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 102, 204, 0.3);
}

.btn-outline-primary {
    color: var(--primary-blue);
    border-color: var(--primary-blue);
    transition: all 0.3s ease;
}

.btn-outline-primary:hover {
    background-color: var(--primary-blue);
    border-color: var(--primary-blue);
    transform: translateY(-2px);
}

/* Cards */
.article-card {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    transition: all 0.3s ease;
}

.article-card:hover {
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    transform: translateY(-4px);
}

.article-card .card-title a {
    color: var(--text-dark);
    font-weight: 600;
    font-size: 1.1rem;
}

.article-card .card-title a:hover {
    color: var(--primary-blue);
}

/* Badges */
.badge-primary {
    background-color: var(--primary-blue);
    padding: 0.4rem 0.8rem;
    font-weight: 500;
    font-size: 0.75rem;
}

.badge-secondary {
    background-color: #6c757d;
    padding: 0.4rem 0.8rem;
    font-weight: 500;
    font-size: 0.75rem;
}

.badge-info {
    background-color: #17a2b8;
    padding: 0.4rem 0.8rem;
    font-weight: 500;
    font-size: 0.75rem;
}

/* Page Header */
.page-header {
    background: linear-gradient(135deg, var(--light-blue) 0%, #ffffff 100%);
}

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--dark-blue) 100%);
    color: white;
}

.cta-section h2 {
    color: white;
}

.cta-section .btn-light {
    background-color: white;
    color: var(--primary-blue);
    border: none;
    font-weight: 600;
    padding: 0.75rem 2rem;
}

.cta-section .btn-light:hover {
    background-color: var(--light-blue);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.3);
}

/* Article Content */
.article-content {
    font-size: 1.1rem;
    line-height: 1.8;
}

.article-content h2 {
    color: var(--text-dark);
    font-weight: 700;
    margin-top: 2rem;
}

.article-content h3 {
    color: var(--text-dark);
    font-weight: 600;
}

.article-content p {
    margin-bottom: 1.5rem;
}

.article-content ul,
.article-content ol {
    margin-bottom: 1.5rem;
    padding-left: 1.5rem;
}

.article-content li {
    margin-bottom: 0.75rem;
}

/* Related Articles */
.related-articles .card {
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.related-articles .card:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
}

.related-articles .card-title a {
    color: var(--text-dark);
    font-weight: 600;
    font-size: 1rem;
}

.related-articles .card-title a:hover {
    color: var(--primary-blue);
}

/* Footer */
footer {
    background-color: #1a1a1a;
}

footer a {
    transition: color 0.3s ease;
}

footer a:hover {
    color: var(--primary-blue) !important;
}

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

/* Contact Form */
.form-control:focus {
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 0.2rem rgba(0, 102, 204, 0.25);
}

/* Responsive Adjustments */
@media (max-width: 768px) {
    .hero-section {
        padding: 2rem 0;
    }
    
    .display-4 {
        font-size: 2rem;
    }
    
    .article-content {
        font-size: 1rem;
    }
    
    .btn-lg {
        padding: 0.5rem 1.5rem;
        font-size: 1rem;
    }
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Loading Animation for Images */
img {
    max-width: 100%;
    height: auto;
}

/* Print Styles */
@media print {
    .navbar,
    footer,
    .btn,
    .related-articles {
        display: none;
    }
    
    .article-content {
        font-size: 12pt;
    }
}