* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

.hidden {
    display: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background: linear-gradient(135deg, #2c5aa0 0%, #1e3a66 100%);
    color: white;
    padding: 1rem 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

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

.header-nav {
    margin-left: auto;
    display: flex;
    gap: 0.5rem;
}

.catalog-link {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1.5rem;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    font-weight: 600;
    transition: background 0.3s;
}

.catalog-link:hover {
    background: rgba(255, 255, 255, 0.2);
}

header h1 {
    font-size: 2rem;
    margin-bottom: 0.25rem;
}

.subtitle {
    font-size: 1rem;
    opacity: 0.9;
}

main {
    padding: 2rem 0;
}

/* Catalog page removes default padding as layout handles it */
main.catalog-layout {
    padding: 0;
}

section {
    background: white;
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

#intro {
    font-size: 1.1rem;
    color: #555;
}

#controls {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: flex-end;
}

.control-group {
    flex: 1;
    min-width: 200px;
}

.control-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #2c5aa0;
}

.control-group select,
.control-group button {
    width: 100%;
    padding: 0.75rem;
    font-size: 1rem;
    border: 2px solid #ddd;
    border-radius: 4px;
    background: white;
}

.control-group select:focus {
    outline: none;
    border-color: #2c5aa0;
}

button {
    background: #2c5aa0;
    color: white;
    border: none;
    cursor: pointer;
    font-weight: 600;
    transition: background 0.3s;
}

button:hover:not(:disabled) {
    background: #1e3a66;
}

button:disabled {
    background: #ccc;
    cursor: not-allowed;
}

h2 {
    color: #2c5aa0;
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

#resource-metadata {
    padding: 1rem;
    background: #f8f9fa;
    border-left: 4px solid #2c5aa0;
    border-radius: 4px;
}

#resource-metadata h3 {
    color: #2c5aa0;
    margin-bottom: 0.5rem;
}

#resource-metadata p {
    margin-bottom: 0.5rem;
    color: #555;
}

#article-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
}

.article-item {
    padding: 1rem;
    background: #f8f9fa;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s;
}

.article-item:hover {
    background: #e8f4f8;
    border-color: #2c5aa0;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.article-item h4 {
    color: #2c5aa0;
    margin-bottom: 0.5rem;
}

.article-item p {
    font-size: 0.9rem;
    color: #666;
}

#content-display {
    padding: 1.5rem;
    background: #fafafa;
    border-radius: 4px;
    min-height: 200px;
}

#content-display h3 {
    color: #2c5aa0;
    margin-bottom: 1rem;
}

#content-display .content-body {
    line-height: 1.8;
}

.loading {
    text-align: center;
    padding: 2rem;
    color: #666;
    font-style: italic;
}

.error {
    padding: 1rem;
    background: #fee;
    border-left: 4px solid #c00;
    border-radius: 4px;
    color: #c00;
}

footer {
    background: #2c5aa0;
    color: white;
    padding: 1rem 0;
    margin-top: 1.5rem;
    text-align: center;
}

footer a {
    color: #add8e6;
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

footer p {
    margin-bottom: 0.25rem;
}

.metadata-grid {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 0.5rem 1rem;
}

.metadata-label {
    font-weight: 600;
    color: #2c5aa0;
}

.metadata-value {
    color: #555;
}

/* Resource header styles */
.resource-header {
    margin-bottom: 1.5rem;
}

.resource-header h3 {
    color: #2c5aa0;
    margin-bottom: 0.5rem;
}

/* Two-column layout for resource details */
.resource-details-columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-top: 1.5rem;
}

.resource-info-column,
.resource-access-column {
    min-width: 0; /* Prevent overflow */
}

.resource-info-column h3,
.resource-access-column h3 {
    color: #2c5aa0;
    margin-bottom: 1rem;
}

@media (max-width: 768px) {
    #controls {
        flex-direction: column;
    }
    
    .control-group {
        width: 100%;
    }
    
    #article-list {
        grid-template-columns: 1fr;
    }
    
    /* Stack columns on mobile */
    .resource-details-columns {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
}

/* Informational page styles */
.content-section {
    background: white;
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.content-section h2 {
    color: #2c5aa0;
    margin-bottom: 1rem;
    font-size: 1.8rem;
}

.content-section p {
    margin-bottom: 1rem;
    line-height: 1.8;
    color: #555;
}

.content-section a {
    color: #2c5aa0;
    text-decoration: none;
}

.content-section a:hover {
    text-decoration: underline;
}

.content-section code {
    background: #f4f4f4;
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
}

.cta-section {
    background: linear-gradient(135deg, #2c5aa0 0%, #1e3a66 100%);
    color: white;
    text-align: center;
    padding: 3rem 2rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.cta-section h2 {
    color: white;
    margin-bottom: 1rem;
    font-size: 2rem;
}

.cta-section p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
}

.cta-button {
    display: inline-block;
    padding: 1rem 2rem;
    background: white;
    color: #2c5aa0;
    text-decoration: none;
    border-radius: 4px;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.3);
}

/* Download list styling */
.download-list {
    margin-left: 2rem;
    margin-top: 1rem;
}

.download-list li {
    margin-bottom: 0.5rem;
}

/* Citation styling */
.citation {
    font-size: 1rem;
    line-height: 1.8;
    color: #555;
    padding: 1rem;
    background: #f8f9fa;
    border-left: 4px solid #2c5aa0;
    border-radius: 4px;
}

.adaptation-notice {
    font-size: 1rem;
    line-height: 1.8;
    color: #555;
    padding: 1rem;
    background: #f8f9fa;
    border-left: 4px solid #2c5aa0;
    border-radius: 4px;
}

/* Breadcrumb navigation */
.breadcrumb {
    background: white;
    padding: 1rem 0;
    border-bottom: 1px solid #e0e0e0;
}

.breadcrumb a {
    color: #2c5aa0;
    text-decoration: none;
}

.breadcrumb a:hover {
    text-decoration: underline;
}

/* Catalog page specific styles */
#catalog-controls {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: flex-end;
}

/* Catalog sidebar layout */
.catalog-layout {
    display: flex;
    gap: 2rem;
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem 20px;
    align-items: flex-start;
}

.catalog-sidebar {
    flex: 0 0 300px;
    position: sticky;
    top: 2rem; /* Space from viewport top when sticky */
    max-height: calc(100vh - 4rem); /* Viewport height minus top/bottom spacing (2rem each) */
    overflow-y: auto;
}

.catalog-sidebar section {
    background: white;
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    margin-bottom: 0;
}

.catalog-sidebar h2 {
    font-size: 1.3rem;
    margin-bottom: 1.5rem;
    color: #2c5aa0;
}

.catalog-sidebar .control-group {
    margin-bottom: 1.5rem;
}

.catalog-sidebar .control-group:last-child {
    margin-bottom: 0;
}

.catalog-sidebar #catalog-controls {
    display: block;
}

.catalog-content {
    flex: 1;
    min-width: 0;
}

.catalog-content section {
    background: white;
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.catalog-content section:last-child {
    margin-bottom: 0;
}

/* Tab styles for catalog content viewer */
.tabs {
    display: flex;
    border-bottom: 2px solid #e0e0e0;
    margin-bottom: 1.5rem;
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    color: #666;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.tab-btn:hover {
    color: #2c5aa0;
    background: #f8f9fa;
}

.tab-btn.active {
    color: #2c5aa0;
    border-bottom-color: #2c5aa0;
    background: none;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Preview content styles */
#preview-display {
    min-height: 200px;
}

.preview-content {
    padding: 1rem;
    background: #fafafa;
    border-radius: 4px;
    line-height: 1.8;
}

/* RTL (right-to-left) language support */
.preview-content[dir="rtl"] {
    text-align: right;
}

.preview-content h1,
.preview-content h2,
.preview-content h3 {
    color: #2c5aa0;
    margin-top: 1rem;
    margin-bottom: 0.5rem;
}

.preview-content h1 {
    font-size: 1.5rem;
}

.preview-content h2 {
    font-size: 1.3rem;
}

.preview-content h3 {
    font-size: 1.1rem;
}

.preview-content p {
    margin-bottom: 1rem;
}

.preview-content a {
    color: #2c5aa0;
    text-decoration: none;
}

.preview-content a:hover {
    text-decoration: underline;
}

.loading-message {
    text-align: center;
    color: #666;
    font-style: italic;
    padding: 2rem;
}

.no-preview {
    text-align: center;
    color: #666;
    padding: 2rem;
    background: #f8f9fa;
    border-radius: 4px;
}

.error-message {
    text-align: center;
    color: #c00;
    padding: 2rem;
    background: #fee;
    border-radius: 4px;
}

/* Preview navigation styles */
.preview-navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    margin-bottom: 1rem;
    background: #f8f9fa;
    border-radius: 4px;
    border: 1px solid #e0e0e0;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: #2c5aa0;
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s, opacity 0.3s;
}

.nav-btn:hover:not(:disabled) {
    background: #1e3a66;
}

.nav-btn:disabled {
    background: #ccc;
    cursor: not-allowed;
    opacity: 0.6;
}

.nav-arrow {
    font-weight: bold;
}

.article-position {
    font-weight: 600;
    color: #555;
    font-size: 0.95rem;
}

/* Responsive design for mobile */
@media (max-width: 768px) {
    .catalog-layout {
        flex-direction: column;
        padding: 1rem 20px;
    }
    
    .catalog-sidebar {
        flex: 0 0 auto;
        width: 100%;
        position: static;
        max-height: none;
    }
    
    .catalog-content {
        width: 100%;
    }
    
    .tabs {
        flex-wrap: wrap;
    }
    
    .tab-btn {
        flex: 1;
        text-align: center;
        padding: 0.75rem 0.5rem;
    }
    
    /* Mobile preview navigation */
    .preview-navigation {
        flex-wrap: wrap;
        gap: 0.5rem;
        justify-content: center;
    }
    
    .article-position {
        order: -1;
        width: 100%;
        text-align: center;
        margin-bottom: 0.25rem;
    }
    
    .nav-btn {
        flex: 1;
        justify-content: center;
        padding: 0.75rem 0.5rem;
    }
}