/* ConfIndex - Academic Conference Search */
/* Cloudflare Pages Static Version */

/* Design Tokens - CSS Custom Properties */
:root {
    /* Primary Colors */
    --color-primary: #2563EB;
    --color-primary-hover: #1D4ED8;
    --color-primary-light: #EFF6FF;
    --color-primary-border: #93C5FD;
    --color-primary-ring: rgba(59, 130, 246, 0.3);

    /* Neutral Colors */
    --color-bg: #F9FAFB;
    --color-surface: #FFFFFF;
    --color-border: #E5E7EB;
    --color-border-light: #D1D5DB;

    /* Text Colors (WCAG AA compliant - 4.5:1 minimum) */
    --color-text-primary: #111827;
    --color-text-secondary: #374151;
    --color-text-muted: #4B5563;
    --color-text-subtle: #6B7280;

    /* Status Colors */
    --color-danger: #DC2626;
    --color-success: #047857;
    --color-warning: #B45309;

    /* Badge Colors */
    --badge-blue-bg: #DBEAFE;
    --badge-blue-text: #1D4ED8;
    --badge-purple-bg: #EDE9FE;
    --badge-purple-text: #6D28D9;
    --badge-gray-bg: #F3F4F6;
    --badge-gray-text: #4B5563;
    --badge-green-bg: #D1FAE5;
    --badge-green-text: #047857;
    --badge-yellow-bg: #FEF3C7;
    --badge-yellow-text: #B45309;
    --badge-indigo-bg: #E0E7FF;
    --badge-indigo-text: #4338CA;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;

    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 12px rgba(0, 0, 0, 0.1);

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;

    /* Focus */
    --focus-ring: 2px solid var(--color-primary);
    --focus-offset: 2px;
}

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

body {
    font-family: var(--font-family);
    background: var(--color-bg);
    color: var(--color-text-primary);
    line-height: 1.5;
    min-height: 100vh;
}

/* Layout */
.container {
    max-width: 80rem;
    margin-left: auto;
    margin-right: auto;
    padding-left: 1rem;
    padding-right: 1rem;
}

@media (min-width: 640px) {
    .container { padding-left: 1.5rem; padding-right: 1.5rem; }
}

@media (min-width: 1024px) {
    .container { padding-left: 2rem; padding-right: 2rem; }
}

.hidden { display: none !important; }

/* Header */
.header {
    background: var(--color-surface);
    box-shadow: var(--shadow-sm);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-md) 0;
}

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

.header h1 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
}

.header .subtitle {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    margin-top: var(--space-xs);
}

.header .updated {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
}

/* Search & Filters */
.search-section {
    background: var(--color-surface);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    padding: var(--space-md) var(--space-lg);
    margin-top: var(--space-lg);
}

.search-bar {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.search-input {
    flex: 1;
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.search-input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 2px var(--color-primary-ring);
}

.btn-primary {
    padding: var(--space-sm) var(--space-lg);
    background: var(--color-primary);
    color: var(--color-surface);
    border-radius: var(--radius-md);
    border: none;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-primary:hover { background: var(--color-primary-hover); }
.btn-primary:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}

.btn-outline {
    padding: 0.375rem 0.75rem;
    color: var(--color-primary);
    border: 1px solid var(--color-primary-border);
    border-radius: var(--radius-sm);
    background: transparent;
    cursor: pointer;
    font-size: var(--font-size-sm);
    transition: background 0.2s;
}

.btn-outline:hover { background: var(--color-primary-light); }
.btn-outline:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}

/* Filter Grid */
.filter-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
}

@media (min-width: 640px) {
    .filter-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (min-width: 1024px) {
    .filter-grid { grid-template-columns: repeat(6, 1fr); }
}

.filter-label {
    display: block;
    font-size: var(--font-size-xs);
    font-weight: 500;
    color: var(--color-text-muted);
    margin-bottom: var(--space-xs);
}

.filter-select {
    width: 100%;
    padding: 0.375rem 0.625rem;
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    background: var(--color-surface);
    cursor: pointer;
}

.filter-select.filter-active {
    background: var(--color-primary-light);
    border-color: var(--color-primary);
}
.filter-select:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
    border-color: var(--color-primary);
}

/* Results Info */
.results-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: var(--space-md);
    margin-bottom: var(--space-sm);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.expand-toggle {
    font-size: var(--font-size-xs);
    color: var(--color-primary);
    background: none;
    border: none;
    cursor: pointer;
}

.expand-toggle:hover { text-decoration: underline; }
.expand-toggle:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
    border-radius: 2px;
}

/* Event Cards */
.event-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-top: var(--space-sm);
    margin-bottom: var(--space-xl);
}

.event-card {
    background: var(--color-surface);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: all 0.2s ease;
}

.event-card:hover { border-color: var(--color-primary-border); }
.event-card[open] {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-lg);
}

.event-card summary {
    cursor: pointer;
    list-style: none;
    padding: var(--space-md);
}

.event-card summary::-webkit-details-marker { display: none; }
.event-card summary::marker { display: none; }
.event-card summary:focus-visible {
    outline: var(--focus-ring);
    outline-offset: -2px;
    border-radius: var(--radius-md);
}

.event-card[open] .chevron { transform: rotate(180deg); }

.chevron {
    width: 1.25rem;
    height: 1.25rem;
    color: var(--color-text-muted);
    transition: transform 0.2s ease;
}

.event-card.hidden-by-filter { display: none; }

/* Event Card Header */
.event-header {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

@media (min-width: 640px) {
    .event-header {
        flex-direction: row;
        align-items: flex-start;
        justify-content: space-between;
    }
}

.event-title-row {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.event-title {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text-primary);
}

.event-summary-ko {
    margin-top: var(--space-xs);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.event-meta {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-xs) var(--space-md);
    margin-top: var(--space-xs);
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

.event-badges {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-shrink: 0;
}

/* Badges */
.badge {
    display: inline-block;
    padding: 0.125rem var(--space-sm);
    border-radius: var(--radius-full);
    font-size: var(--font-size-xs);
    font-weight: 500;
}

.badge-blue { background: var(--badge-blue-bg); color: var(--badge-blue-text); }
.badge-purple { background: var(--badge-purple-bg); color: var(--badge-purple-text); }
.badge-gray { background: var(--badge-gray-bg); color: var(--badge-gray-text); }
.badge-green { background: var(--badge-green-bg); color: var(--badge-green-text); }
.badge-yellow { background: var(--badge-yellow-bg); color: var(--badge-yellow-text); }
.badge-indigo { background: var(--badge-indigo-bg); color: var(--badge-indigo-text); }

/* Event Detail */
.event-detail {
    padding: 0 var(--space-md) var(--space-md);
    border-top: 1px solid var(--color-border);
    background: var(--color-bg);
}

.detail-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
    margin-top: 1rem;
}

@media (min-width: 640px) {
    .detail-grid { grid-template-columns: repeat(2, 1fr); }
}

.detail-section h4 {
    font-size: var(--font-size-xs);
    font-weight: 600;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-sm);
}

.detail-row {
    display: flex;
    gap: var(--space-sm);
    font-size: var(--font-size-sm);
}

.detail-row dt {
    color: var(--color-text-muted);
    min-width: 80px;
}

.detail-row dd { font-weight: 500; }

.deadline-passed {
    text-decoration: line-through;
    color: var(--color-text-muted) !important;
}

.deadline-active { color: var(--color-danger); }

/* Description */
.event-description {
    margin-top: var(--space-md);
}

.event-description p {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: 1.625;
    white-space: pre-line;
}

/* Topics */
.event-topics {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
    margin-top: 0.75rem;
}

.topic-tag {
    display: inline-block;
    padding: 0.125rem var(--space-sm);
    background: var(--color-primary-light);
    color: var(--color-primary);
    border-radius: var(--radius-full);
    font-size: var(--font-size-xs);
    font-weight: 500;
}

/* Links */
.event-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: var(--space-md);
}

.link-primary {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: 0.375rem 0.75rem;
    background: var(--color-primary);
    color: var(--color-surface);
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-size: var(--font-size-sm);
    transition: background 0.2s;
}

.link-primary:hover { background: var(--color-primary-hover); }
.link-primary:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}

.link-secondary {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: 0.375rem 0.75rem;
    background: var(--color-border);
    color: var(--color-text-secondary);
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-size: var(--font-size-sm);
    transition: background 0.2s;
}

.link-secondary:hover { background: var(--color-border-light); }
.link-secondary:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}

/* Event Meta Footer */
.event-footer {
    margin-top: 0.75rem;
    padding-top: var(--space-sm);
    border-top: 1px solid var(--color-border);
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
}

/* No Results */
.no-results {
    text-align: center;
    padding: var(--space-2xl) var(--space-md);
    color: var(--color-text-muted);
}

.no-results svg {
    width: 3rem;
    height: 3rem;
    color: var(--color-border-light);
    margin: 0 auto var(--space-md);
}

.no-results p {
    font-size: var(--font-size-lg);
    font-weight: 500;
}

.no-results .hint {
    font-size: var(--font-size-sm);
    margin-top: var(--space-xs);
}

/* Loading */
.loading {
    text-align: center;
    padding: var(--space-2xl) var(--space-md);
    color: var(--color-text-muted);
}

.loading-spinner {
    width: 2rem;
    height: 2rem;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--space-md);
}

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

/* Footer */
.footer {
    text-align: center;
    padding: var(--space-xl) var(--space-md);
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    border-top: 1px solid var(--color-border);
    background: var(--color-surface);
}

.footer-content {
    max-width: 600px;
    margin: 0 auto;
}

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

.footer-link {
    font-weight: 500;
    font-size: var(--font-size-sm);
    color: var(--color-primary);
    transition: color 0.2s ease;
}

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

.footer a:hover { text-decoration: underline; }
.footer a:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}

/* Language Switcher */
.lang-switcher {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}
.lang-btn {
    background: transparent;
    border: none;
    color: var(--color-text-muted);
    font-size: var(--font-size-xs);
    font-weight: 500;
    cursor: pointer;
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-sm);
}
.lang-btn:hover { color: var(--color-primary); }
.lang-btn.active {
    color: var(--color-primary);
    background: var(--color-primary-light);
    font-weight: 600;
}
.lang-btn:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}
.lang-divider { color: var(--color-border-light); }

/* Tab Navigation */
.tab-nav {
    display: flex;
    gap: 0;
    border-bottom: 1px solid var(--color-border);
    margin-top: var(--space-sm);
}
.tab-link {
    padding: 0.75rem var(--space-lg);
    text-decoration: none;
    color: var(--color-text-muted);
    font-weight: 500;
    border-bottom: 2px solid transparent;
    margin-bottom: -1px;
}
.tab-link:hover { color: var(--color-primary); }
.tab-link.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
    font-weight: 600;
}
.tab-link:focus-visible {
    outline: var(--focus-ring);
    outline-offset: -2px;
}

/* About Page Styles */
.about-hero {
    text-align: center;
    padding: var(--space-2xl) var(--space-md);
    background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-surface) 100%);
}
.about-preheadline {
    font-size: var(--font-size-sm);
    color: var(--color-primary);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-sm);
}
.about-title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: var(--space-md);
}
@media (min-width: 640px) {
    .about-title { font-size: 2.5rem; }
}
.about-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto var(--space-lg);
    line-height: 1.6;
}
.about-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
    flex-wrap: wrap;
}
.stat-item {
    text-align: center;
}
.stat-value {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-primary);
}
.stat-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}
.about-cta {
    display: inline-block;
    padding: 0.75rem var(--space-xl);
    background: var(--color-primary);
    color: var(--color-surface);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    margin-bottom: var(--space-xl);
}
.about-cta:hover { background: var(--color-primary-hover); }
.about-cta:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}

/* Product Preview */
.product-preview {
    max-width: 800px;
    margin: 2rem auto 0;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    border: 1px solid var(--color-border);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}
.product-preview-placeholder {
    background: var(--color-border);
    border-radius: var(--radius-sm);
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}
.product-screenshot {
    width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    display: block;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

/* About Sections */
.about-section {
    padding: var(--space-2xl) var(--space-md);
}
.about-section:nth-child(even) {
    background: var(--color-bg);
}
.section-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
    text-align: center;
    margin-bottom: var(--space-sm);
}
.section-description {
    text-align: center;
    color: var(--color-text-muted);
    margin-bottom: var(--space-xl);
}

/* Data Sources Grid */
.sources-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
    max-width: 800px;
    margin: 0 auto;
}
@media (min-width: 640px) {
    .sources-grid { grid-template-columns: repeat(3, 1fr); }
}
@media (min-width: 1024px) {
    .sources-grid { grid-template-columns: repeat(5, 1fr); }
}
.source-item {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    text-align: center;
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-secondary);
}
.source-item:hover {
    border-color: var(--color-primary-border);
    background: var(--color-primary-light);
}
.source-item:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}

/* Use Cases Grid */
.usecases-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-lg);
    max-width: 900px;
    margin: 0 auto;
}
@media (min-width: 768px) {
    .usecases-grid { grid-template-columns: repeat(3, 1fr); }
}
.usecase-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    text-align: center;
}
.usecase-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--space-md);
    background: var(--color-primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-primary);
}
.usecase-icon svg {
    width: 32px;
    height: 32px;
}
.usecase-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: 0.75rem;
}
.usecase-list {
    list-style: none;
    padding: 0;
    margin: 0;
    text-align: left;
}
.usecase-list li {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    padding: 0.375rem 0;
    padding-left: 1.25rem;
    position: relative;
}
.usecase-list li::before {
    content: "\2022";
    position: absolute;
    left: 0;
    color: var(--color-primary);
}

/* Contact Section */
.contact-section {
    text-align: center;
    padding: var(--space-2xl) var(--space-md);
    background: var(--color-bg);
}
.contact-email {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
    margin: var(--space-md) 0;
}
.contact-cta {
    display: inline-block;
    padding: 0.625rem var(--space-lg);
    border: 1px solid var(--color-primary);
    color: var(--color-primary);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-weight: 500;
}
.contact-cta:hover {
    background: var(--color-primary-light);
}
.contact-cta:focus-visible {
    outline: var(--focus-ring);
    outline-offset: var(--focus-offset);
}