/* CSS Variables for Theme Support - UPDATED: Light Colors */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --text-muted: #adb5bd;
    --border-color: #dee2e6;
    --shadow: rgba(0, 0, 0, 0.1);
    --accent-primary: #a8c8ec;
    --accent-secondary: #b8a8d8;
    --success: #a8d5a8;
    --warning: #f5d5a8;
    --danger: #f5a8a8;
    --info: #a8d5d5;
}

/* Dark Mode Variables */
[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-tertiary: #404040;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --text-muted: #808080;
    --border-color: #404040;
    --shadow: rgba(0, 0, 0, 0.3);
    --accent-primary: #7c3aed;
    --accent-secondary: #a855f7;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #e8f4fd 0%, #f0e8fd 100%);
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Dark Mode Toggle */
.dark-mode-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    background: var(--bg-primary);
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px var(--shadow);
}

.dark-mode-toggle:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 16px var(--shadow);
}

/* Connection mode banner - ADDED */
.connection-banner {
    position: sticky;
    top: 0;
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 10px 44px 10px 16px;
    font-size: 14px;
    background: var(--info);
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-color);
}
.connection-banner.demo-mode {
    background: var(--warning);
}
.connection-banner.hidden {
    display: none;
}
.connection-banner-dismiss {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: transparent;
    border: none;
    font-size: 20px;
    cursor: pointer;
    padding: 0 6px;
    line-height: 1;
    color: var(--text-primary);
}
.connection-banner-dismiss:hover {
    opacity: 0.8;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    background: var(--bg-primary);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 20px 40px var(--shadow);
    backdrop-filter: blur(10px);
    transition: background-color 0.3s ease;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 30px;
}

.header h1 {
    color: var(--text-primary);
    font-size: 2.5em;
    margin-bottom: 10px;
    background: linear-gradient(45deg, #a8c8ec, #b8a8d8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header p {
    color: var(--text-secondary);
    font-size: 1.1em;
    margin-bottom: 20px;
}

/* Metrics Panel */
.metrics-panel {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
    padding: 20px;
    background: var(--bg-secondary);
    border-radius: 15px;
    border: 1px solid var(--border-color);
}

.metric {
    text-align: center;
    padding: 15px;
    background: var(--bg-primary);
    border-radius: 10px;
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease;
}

.metric:hover {
    transform: translateY(-2px);
}

.metric-label {
    display: block;
    font-size: 0.9em;
    color: var(--text-secondary);
    margin-bottom: 5px;
    font-weight: 500;
}

.metric-value {
    display: block;
    font-size: 1.4em;
    font-weight: bold;
    color: var(--accent-primary);
}

/* Search Section */
.search-section {
    margin-bottom: 30px;
}

.search-container {
    max-width: 800px;
    margin: 0 auto;
}

.search-input-container {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

#searchInput {
    flex: 1;
    padding: 15px 20px;
    border: 2px solid var(--border-color);
    border-radius: 25px;
    font-size: 1.1em;
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

#searchInput:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.search-btn {
    padding: 15px 25px;
    background: linear-gradient(45deg, #a8c8ec, #b8a8d8);
    color: #2c3e50;
    border: none;
    border-radius: 25px;
    font-size: 1.1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.search-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(168, 200, 236, 0.4);
}

.search-btn:active {
    transform: translateY(0);
}

/* Example Queries */
.example-queries {
    margin-top: 20px;
}

.example-queries h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
    font-size: 1.1em;
}

.query-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.example-query {
    padding: 10px 20px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.9em;
}

.example-query:hover {
    background: #a8c8ec;
    color: #2c3e50;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(168, 200, 236, 0.4);
}

/* Filters Section */
.filters-section {
    margin-bottom: 30px;
    padding: 20px;
    background: var(--bg-secondary);
    border-radius: 15px;
    border: 1px solid var(--border-color);
}

.filters-container h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
    font-size: 1.2em;
}

.filters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.filter-group {
    display: flex;
    flex-direction: column;
    gap: 5px;
}

.filter-group label {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9em;
}

.filter-group select,
.filter-group input {
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.9em;
    transition: border-color 0.3s ease;
}

.filter-group select:focus,
.filter-group input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

/* Results Section */
.results-section {
    margin-bottom: 30px;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border-color);
}

.results-header h2 {
    color: var(--text-primary);
    font-size: 1.5em;
}

.results-count {
    color: var(--text-secondary);
    font-size: 0.9em;
}

/* Loading State */
.loading-state {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

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

/* Empty State */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
}

.empty-icon {
    font-size: 4em;
    margin-bottom: 20px;
}

.empty-state h3 {
    color: var(--text-primary);
    margin-bottom: 10px;
    font-size: 1.3em;
}

/* Results Container */
.results-container {
    display: grid;
    gap: 20px;
}

.result-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 15px;
    padding: 25px;
    transition: all 0.3s ease;
    cursor: pointer;
}

.result-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px var(--shadow);
    border-color: var(--accent-primary);
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
}

.result-title {
    color: var(--text-primary);
    font-size: 1.2em;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 10px;
}

.result-similarity {
    background: linear-gradient(45deg, #a8c8ec, #b8a8d8);
    color: #2c3e50;
    padding: 5px 12px;
    border-radius: 15px;
    font-size: 0.9em;
    font-weight: 600;
    white-space: nowrap;
    margin-left: 15px;
}

.result-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 15px;
    font-size: 0.9em;
    color: var(--text-secondary);
}

.result-meta span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.result-authors {
    color: var(--text-primary);
    font-weight: 500;
    margin-bottom: 10px;
}

.result-abstract {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 15px;
}

.result-keywords {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.keyword-tag {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 0.8em;
    border: 1px solid var(--border-color);
}

/* Pagination */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    margin-top: 30px;
    padding: 20px;
}

.pagination-btn {
    padding: 10px 20px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
}

.pagination-btn:hover:not(:disabled) {
    background: #a8c8ec;
    color: #2c3e50;
}

.pagination-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.pagination-info {
    color: var(--text-secondary);
    font-size: 0.9em;
}

/* Footer */
/* Q&A section - ADDED */
.qa-section {
    margin: 32px 0;
    padding: 24px;
    background: var(--bg-secondary);
    border-radius: 12px;
    border: 1px solid var(--border-color);
}
.qa-section h2 { margin-bottom: 12px; }
.qa-input-container {
    display: flex;
    gap: 12px;
    margin-bottom: 16px;
}
.qa-input-container input {
    flex: 1;
    padding: 10px 14px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
}
.qa-result .qa-answer,
.qa-result .qa-sources { margin-top: 16px; }
.qa-result .qa-answer h3,
.qa-result .qa-sources h3 { margin-bottom: 8px; font-size: 1rem; }
.qa-sources .source-item {
    padding: 10px;
    margin: 8px 0;
    background: var(--bg-primary);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}
.qa-sources .source-item a { color: var(--accent-primary); }
.qa-loading, .qa-error { margin-top: 12px; }
.qa-error { color: var(--danger); }

.footer {
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.footer-content p {
    color: var(--text-secondary);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: var(--accent-secondary);
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    
    .container {
        padding: 20px;
        border-radius: 15px;
    }
    
    .header h1 {
        font-size: 2em;
    }
    
    .metrics-panel {
        grid-template-columns: repeat(2, 1fr);
        gap: 15px;
        padding: 15px;
    }
    
    .search-input-container {
        flex-direction: column;
    }
    
    .filters-grid {
        grid-template-columns: 1fr;
    }
    
    .results-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .result-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .result-similarity {
        margin-left: 0;
    }
    
    .footer-links {
        flex-direction: column;
        gap: 10px;
    }
    
    .dark-mode-toggle {
        top: 10px;
        right: 10px;
        width: 45px;
        height: 45px;
    }
}

@media (max-width: 480px) {
    .metrics-panel {
        grid-template-columns: 1fr;
    }
    
    .query-tabs {
        justify-content: flex-start;
    }
    
    .example-query {
        font-size: 0.8em;
        padding: 8px 15px;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for keyboard navigation */
button:focus,
input:focus,
select:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000000;
        --shadow: rgba(0, 0, 0, 0.5);
    }
    
    [data-theme="dark"] {
        --border-color: #ffffff;
        --shadow: rgba(255, 255, 255, 0.3);
    }
}