/* Base Variables - Light Theme */
:root {
    --color-bg: #f8fafc;
    --color-bg-secondary: #ffffff;
    --color-bg-tertiary: #f1f5f9;
    --color-text: #1e293b;
    --color-text-secondary: #475569;
    --color-text-muted: #64748b;
    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-accent: #7c3aed;
    --color-success: #16a34a;
    --color-warning: #ca8a04;
    --color-danger: #dc2626;
    --color-border: #e2e8f0;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
    --transition: 0.2s ease;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition);
}

a:hover {
    color: var(--color-primary-hover);
}

/* Navbar */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background: var(--color-bg-secondary);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text);
}

.nav-icon {
    width: 28px;
    height: 28px;
    color: var(--color-primary);
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--color-text-secondary);
    font-weight: 500;
    padding: 0.5rem 0;
    border-bottom: 2px solid transparent;
    transition: all var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--color-text);
    border-bottom-color: var(--color-primary);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* Page Header */
.page-header {
    text-align: center;
    margin-bottom: 3rem;
}

.page-header h1 {
    margin-bottom: 0.5rem;
    color: var(--color-text);
}

.subtitle {
    color: var(--color-text-secondary);
    font-size: 1.1rem;
}

/* Search Section */
.search-section {
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    padding: 2rem;
    margin-bottom: 2rem;
    border: 1px solid var(--color-border);
}

.search-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.search-inputs {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.input-group {
    flex: 1;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.input-group input {
    width: 100%;
    padding: 1rem 1.25rem;
    font-size: 1rem;
    background: var(--color-bg);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    transition: all var(--transition);
}

.input-group input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.input-group input::placeholder {
    color: var(--color-text-muted);
}

.input-hint {
    margin-top: 0.5rem;
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

.relation-arrow {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-primary);
    margin-top: 1.5rem;
}

.relation-arrow svg {
    width: 32px;
    height: 32px;
}

.search-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    padding: 1rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    background: var(--color-primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition);
    align-self: center;
}

.search-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.search-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.search-btn svg {
    width: 20px;
    height: 20px;
}

/* Quick Examples */
.quick-examples {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    gap: 0.25rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--color-border);
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

.examples-label {
    color: var(--color-text-muted);
    margin-right: 0.25rem;
}

.example-link {
    color: var(--color-text-secondary);
    text-decoration: underline;
    text-decoration-style: dashed;
    text-underline-offset: 3px;
    cursor: pointer;
    transition: all var(--transition);
}

.example-link:hover {
    color: var(--color-primary);
    text-decoration-color: var(--color-primary);
}

/* Loading State */
.loading-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 4rem;
    text-align: center;
}

.loader {
    width: 48px;
    height: 48px;
    border: 4px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-state p {
    margin-top: 1rem;
    color: var(--color-text-secondary);
}

.loading-detail {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

/* Results Section */
.results-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.result-card {
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    overflow: hidden;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg-tertiary);
}

.card-header h2,
.card-header h3 {
    margin: 0;
}

.timestamp {
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

/* Summary Card */
.summary-content {
    padding: 1.5rem;
}

.concepts-display {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.concept {
    padding: 0.75rem 1.5rem;
    font-size: 1.125rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    font-family: 'JetBrains Mono', monospace;
}

.concept-a {
    background: rgba(37, 99, 235, 0.1);
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
}

.concept-b {
    background: rgba(124, 58, 237, 0.1);
    border: 2px solid var(--color-accent);
    color: var(--color-accent);
}

.relation-badge {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.relation-badge.positive {
    background: rgba(22, 163, 74, 0.1);
    color: var(--color-success);
}

.relation-badge.negative {
    background: rgba(220, 38, 38, 0.1);
    color: var(--color-danger);
}

.relation-badge.mixed {
    background: rgba(202, 138, 4, 0.1);
    color: var(--color-warning);
}

.relation-badge.neutral {
    background: rgba(100, 116, 139, 0.1);
    color: var(--color-text-muted);
}

/* Strength Meter */
.strength-meter {
    margin-bottom: 2rem;
}

.strength-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.strength-value {
    font-weight: 600;
}

.strength-bar {
    height: 12px;
    background: var(--color-bg);
    border-radius: 6px;
    overflow: hidden;
}

.strength-fill {
    height: 100%;
    border-radius: 6px;
    transition: width 0.6s ease, background 0.3s ease;
    background: var(--color-primary);
}

.strength-score {
    text-align: right;
    margin-top: 0.5rem;
    font-size: 0.875rem;
    color: var(--color-text-muted);
    font-family: 'JetBrains Mono', monospace;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 1rem;
}

.stat-item {
    text-align: center;
    padding: 1rem;
    background: var(--color-bg);
    border-radius: var(--radius-md);
}

.stat-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-text);
    font-family: 'JetBrains Mono', monospace;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 0.25rem;
}

/* Relation Breakdown */
.relation-breakdown {
    padding: 1.5rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.relation-tag {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--color-bg);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
}

.relation-tag.clickable {
    cursor: pointer;
    transition: all 0.15s ease;
}

.relation-tag.clickable:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.25);
}

.relation-tag.clickable:hover .count {
    background: rgba(255, 255, 255, 0.2);
    color: white;
}

.relation-tag .count {
    background: var(--color-bg-tertiary);
    padding: 0.125rem 0.5rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-family: 'JetBrains Mono', monospace;
}

/* Examples List */
.examples-list {
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Article Card Styles */
.article-card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 1rem;
    border-left: 3px solid var(--color-primary);
}

.article-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.article-card-title {
    font-size: 0.95rem;
    font-weight: 600;
    line-height: 1.4;
    flex: 1;
}

.article-card-title a {
    color: var(--color-text);
    text-decoration: none;
}

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

.article-card-authors {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-bottom: 0.25rem;
}

.article-card-journal {
    font-size: 0.8rem;
    font-style: italic;
    color: var(--color-text-muted);
    margin-bottom: 0.5rem;
}

.article-card-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem 1rem;
    font-size: 0.75rem;
    color: var(--color-text-muted);
    margin-bottom: 0.5rem;
}

.article-card-meta a {
    color: var(--color-primary);
    text-decoration: none;
}

.article-card-meta a:hover {
    text-decoration: underline;
}

.article-card-meta .relation-label {
    background: #e0f2fe;
    color: #0369a1;
    padding: 0.1rem 0.4rem;
    border-radius: 4px;
    font-weight: 500;
    font-size: 0.7rem;
}

.article-card-abstract {
    font-size: 0.85rem;
    color: var(--color-text);
    line-height: 1.6;
    background: var(--color-bg-tertiary);
    padding: 0.75rem;
    border-radius: 6px;
    margin-top: 0.5rem;
}

.article-card-abstract.collapsed {
    max-height: 60px;
    overflow: hidden;
    position: relative;
}

.article-card-abstract.collapsed::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 30px;
    background: linear-gradient(transparent, var(--color-bg-tertiary));
}

.article-card-abstract mark,
.article-card-title mark {
    background: #fef08a;
    padding: 0 2px;
    border-radius: 2px;
}

.expand-btn {
    background: none;
    border: none;
    color: var(--color-primary);
    font-size: 0.8rem;
    cursor: pointer;
    padding: 0.25rem 0;
    margin-top: 0.25rem;
}

.expand-btn:hover {
    text-decoration: underline;
}

.quartile-badge {
    font-size: 0.7rem;
    font-weight: 700;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    white-space: nowrap;
}

.quartile-badge.q1 { background: #dcfce7 !important; color: #166534 !important; }
.quartile-badge.q2 { background: #ecfccb !important; color: #3f6212 !important; }
.quartile-badge.q3 { background: #fef9c3 !important; color: #854d0e !important; }
.quartile-badge.q4 { background: #ffedd5 !important; color: #9a3412 !important; }
.quartile-badge.na { background: #f1f5f9 !important; color: #64748b !important; }

/* Legacy example-item styles for backwards compatibility */
.example-item {
    padding: 1rem;
    background: var(--color-bg);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--color-primary);
}

.example-text {
    color: var(--color-text);
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.example-text mark {
    background: rgba(37, 99, 235, 0.15);
    color: var(--color-text);
    padding: 0.1rem 0.3rem;
    border-radius: 3px;
}

.example-text mark.highlight-1 {
    background: rgba(124, 58, 237, 0.15);
}

.example-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

.example-meta a {
    color: var(--color-primary);
}

/* Articles List */
.articles-list {
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.article-link {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.75rem 1rem;
    background: var(--color-bg);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    transition: all var(--transition);
}

.article-link:hover {
    background: var(--color-bg-tertiary);
    transform: translateX(4px);
}

.article-pmid {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.875rem;
    color: var(--color-primary);
    flex-shrink: 0;
}

/* Buttons */
.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    background: var(--color-primary);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    cursor: pointer;
    transition: all var(--transition);
}

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

.btn-primary svg {
    width: 18px;
    height: 18px;
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
    font-weight: 500;
    background: transparent;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition);
}

.btn-secondary:hover {
    background: var(--color-bg-tertiary);
    color: var(--color-text);
}

/* Modal */
.modal {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.4);
}

.modal-content {
    position: relative;
    width: 90%;
    max-width: 800px;
    max-height: 90vh;
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg-tertiary);
}

.modal-close {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    background: transparent;
    border: none;
    color: var(--color-text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--transition);
}

.modal-close:hover {
    background: var(--color-bg);
    color: var(--color-text);
}

.modal-body {
    padding: 1.5rem;
    overflow-y: auto;
}

/* Footer */
.footer {
    text-align: center;
    padding: 2rem;
    margin-top: 3rem;
    border-top: 1px solid var(--color-border);
    color: var(--color-text-muted);
    font-size: 0.875rem;
}

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

.footer a:hover {
    color: var(--color-primary);
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    .navbar {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }
    
    .nav-links {
        gap: 1rem;
    }
    
    .search-inputs {
        flex-direction: column;
    }
    
    .relation-arrow {
        transform: rotate(90deg);
        margin: 0;
    }
    
    .concepts-display {
        flex-direction: column;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}


/* Quartile Distribution Chart */
.quartile-section {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--color-border);
}

.quartile-title {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.quartile-chart {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.quartile-bar-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.quartile-bar-label {
    width: 28px;
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--color-text);
}

.quartile-bar-track {
    flex: 1;
    height: 20px;
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.quartile-bar-fill {
    height: 100%;
    border-radius: var(--radius-sm);
    transition: width 0.3s ease;
}

.quartile-bar-count {
    width: 32px;
    text-align: right;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--color-text-secondary);
}

/* Quartile Badge in Examples */
.quartile-badge {
    display: inline-flex;
    align-items: center;
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-left: 0.5rem;
}