/* ==========================================================================
   DESIGN SYSTEM & VARIABLES (Stripe, Apple, Linear Inspired)
   ========================================================================== */
:root {
    /* Color Palette */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --border-color-hover: #cbd5e1;
    
    /* Brand Accent Colors */
    --primary-color: #2563eb;
    --primary-color-hover: #1d4ed8;
    --primary-color-light: #eff6ff;
    --success-color: #16a34a;
    --success-color-light: #f0fdf4;
    --danger-color: #dc2626;
    --danger-color-light: #fef2f2;
    
    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px -2px rgba(0, 0, 0, 0.05), 0 2px 6px -1px rgba(0, 0, 0, 0.03);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.03);
    
    /* Spacing System (8px Grid) */
    --space-1: 8px;
    --space-2: 16px;
    --space-3: 24px;
    --space-4: 32px;
    --space-6: 48px;
    --space-8: 64px;
    
    /* Border Radius */
    --radius-sm: 6px;
    --radius-default: 12px;
    --radius-lg: 16px;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.16, 1, 0.3, 1);
    --transition-normal: 250ms cubic-bezier(0.16, 1, 0.3, 1);
    
    /* Structure */
    --max-width: 1200px;
    --header-height: 72px;
}

/* ==========================================================================
   RESET & BASE STYLES
   ========================================================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: inherit;
    text-decoration: none;
}

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

select, input, textarea, button {
    font-family: inherit;
    font-size: inherit;
    color: inherit;
    outline: none;
}

/* ==========================================================================
   REUSABLE COMPONENTS (Buttons, Forms)
   ========================================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    height: 40px;
    padding: 0 var(--space-2);
    border-radius: var(--radius-default);
    font-weight: 500;
    font-size: 14px;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 1px solid transparent;
    white-space: nowrap;
}

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

.btn-primary:hover {
    background-color: #27272a; /* Zinc 800 */
    transform: translateY(-1px);
}

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

.btn-secondary {
    background-color: var(--bg-primary);
    color: var(--text-secondary);
    border-color: var(--border-color);
    box-shadow: var(--shadow-sm);
}

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

.btn-block {
    display: flex;
    width: 100%;
}

.btn-clear {
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
    height: 40px;
    padding: 0 var(--space-2);
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 14px;
    cursor: pointer;
    border-radius: var(--radius-default);
    transition: all var(--transition-fast);
}

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

.clear-icon {
    width: 14px;
    height: 14px;
}

/* ==========================================================================
   HEADER NAVIGATION
   ========================================================================== */
.header {
    position: sticky;
    top: 0;
    height: var(--header-height);
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    z-index: 100;
    transition: background-color var(--transition-normal);
}

.header-container {
    max-width: var(--max-width);
    height: 100%;
    margin: 0 auto;
    padding: 0 var(--space-3);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    font-weight: 700;
    font-size: 18px;
    letter-spacing: -0.02em;
    color: var(--text-primary);
}

.logo-icon {
    width: 24px;
    height: 24px;
    color: var(--primary-color);
}

.nav-list {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.nav-link {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
    padding: var(--space-1) 0;
    position: relative;
}

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

.nav-link.active {
    color: var(--primary-color);
}

/* Mobile Nav Toggle */
.mobile-nav-toggle {
    display: none;
    background: transparent;
    border: none;
    cursor: pointer;
    width: 32px;
    height: 32px;
    color: var(--text-primary);
}

.mobile-nav-toggle svg {
    width: 24px;
    height: 24px;
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */
.hero {
    padding: var(--space-8) 0;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    text-align: center;
}

.hero-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 var(--space-3);
    display: flex;
    flex-direction: column;
    align-items: center;
}

.hero-badge {
    display: inline-block;
    padding: 4px 12px;
    background-color: var(--primary-color-light);
    color: var(--primary-color);
    font-size: 12px;
    font-weight: 600;
    border-radius: 100px;
    margin-bottom: var(--space-2);
    letter-spacing: 0.02em;
}

.hero-title {
    font-size: 48px;
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.03em;
    color: var(--text-primary);
    margin-bottom: var(--space-2);
}

.hero-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: var(--space-4);
    max-width: 680px;
}

.hero-stats {
    display: flex;
    gap: var(--space-4);
    margin-bottom: var(--space-4);
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.2;
}

.stat-label {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
}

.hero-cta {
    display: flex;
    gap: var(--space-2);
}

/* ==========================================================================
   ABOUT US & SERVICE OVERVIEW SECTION
   ========================================================================== */
.about-section {
    padding: var(--space-6) 0;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
}

.about-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: var(--space-4);
    align-items: center;
}

.about-badge {
    display: inline-block;
    padding: 4px 12px;
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: 12px;
    font-weight: 600;
    border-radius: 100px;
    margin-bottom: var(--space-2);
}

.about-content h2 {
    font-size: 32px;
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
    margin-bottom: var(--space-2);
    letter-spacing: -0.02em;
}

.about-lead {
    font-size: 17px;
    font-weight: 500;
    color: var(--text-primary);
    line-height: 1.5;
    margin-bottom: var(--space-2);
}

.about-content p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.service-features {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-3);
}

.feature-item {
    display: flex;
    gap: var(--space-2);
}

.feature-icon {
    width: 40px;
    height: 40px;
    background-color: var(--bg-primary);
    color: var(--primary-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.feature-icon svg {
    width: 20px;
    height: 20px;
}

.feature-item h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.feature-item p {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.4;
}

/* ==========================================================================
   DIRECTORY HUB (Search & Filter Section)
   ========================================================================== */
.directory-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--space-6) var(--space-3);
    min-height: 500px;
}

.directory-container .section-header {
    margin-bottom: var(--space-3);
}

/* Sticky Filter Panel */
.filter-panel {
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--space-2) 0;
    margin-bottom: var(--space-3);
    position: sticky;
    top: var(--header-height);
    z-index: 90;
    transition: all var(--transition-normal);
}

.filter-wrapper {
    display: flex;
    gap: var(--space-2);
    align-items: center;
    justify-content: space-between;
}

.search-box {
    position: relative;
    flex: 1;
    max-width: 500px;
}

.search-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    color: var(--text-muted);
    pointer-events: none;
}

.search-input-active .search-icon {
    color: var(--text-primary);
}

.search-box input {
    width: 100%;
    height: 40px;
    padding: 0 var(--space-2) 0 40px;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    font-size: 14px;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.search-box input:focus {
    border-color: var(--text-primary);
    box-shadow: 0 0 0 2px rgba(15, 23, 42, 0.08);
}

.select-filters {
    display: flex;
    gap: var(--space-2);
    align-items: center;
}

.select-wrapper {
    position: relative;
}

.select-wrapper select {
    appearance: none;
    -webkit-appearance: none;
    height: 40px;
    padding: 0 36px 0 16px;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
}

.select-wrapper select:hover {
    border-color: var(--border-color-hover);
    color: var(--text-primary);
}

.select-wrapper select:focus {
    border-color: var(--text-primary);
}

.select-chevron {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    width: 16px;
    height: 16px;
    color: var(--text-muted);
    pointer-events: none;
}

/* Filters Active Summary */
.active-filters-summary {
    padding: var(--space-1) var(--space-2);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-3);
    animation: fadeIn 0.2s ease-out;
}

.results-count {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
}

/* ==========================================================================
   ACCORDION CATEGORY LAYOUT
   ========================================================================== */
.directory-list-wrapper {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.category-accordion-item {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    overflow: hidden;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
}

.category-accordion-item:hover {
    border-color: var(--border-color-hover);
    box-shadow: var(--shadow-md);
}

.category-accordion-item.expanded {
    border-color: var(--text-secondary);
}

.category-header {
    padding: 20px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
    user-select: none;
    background-color: var(--bg-primary);
    transition: background-color var(--transition-fast);
}

.category-header:hover {
    background-color: var(--bg-secondary);
}

.category-title-group {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.category-title-group h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.category-badge-count {
    font-size: 11px;
    font-weight: 600;
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 2px 8px;
    border-radius: 100px;
}

.category-collapse-icon {
    width: 20px;
    height: 20px;
    color: var(--text-secondary);
    transition: transform var(--transition-normal);
}

.category-accordion-item.expanded .category-collapse-icon {
    transform: rotate(180deg);
}

.category-content-wrapper {
    display: none; /* Injected by Javascript display toggle */
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-secondary);
}

.category-accordion-item.expanded .category-content-wrapper {
    display: block;
}

.category-content {
    padding: 24px;
}

.category-desc {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: var(--space-3);
    max-width: 900px;
    line-height: 1.5;
}

/* ==========================================================================
   HORIZONTAL CARD LIST LAYOUT & PAGINATION
   ========================================================================== */
.paginated-conferences-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

/* Horizontal List Card */
.conference-list-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-3);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
}

.conference-list-card:hover {
    border-color: var(--border-color-hover);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.card-main-content {
    flex: 1;
}

.card-badge-row {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 8px;
    align-items: center;
}

.acronym-badge {
    font-size: 10px;
    font-weight: 700;
    color: var(--primary-color);
    background-color: var(--primary-color-light);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    text-transform: uppercase;
}

.online-badge {
    font-size: 10px;
    font-weight: 600;
    color: var(--success-color);
    background-color: var(--success-color-light);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
}

.card-title {
    font-size: 16px;
    font-weight: 600;
    line-height: 1.4;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.card-date-row {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--space-1);
}

.calendar-icon {
    width: 14px;
    height: 14px;
    color: var(--text-muted);
}

.card-description {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
}

.card-action-side {
    flex-shrink: 0;
}

/* Pagination Control Bar */
.pagination-controls {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: var(--space-3);
    padding-top: var(--space-2);
    border-top: 1px solid var(--border-color);
}

.page-indicator {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
}

.pagination-buttons {
    display: flex;
    gap: 8px;
}

.btn-page {
    height: 36px;
    padding: 0 var(--space-2);
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    color: var(--text-secondary);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.btn-page:hover:not(:disabled) {
    background-color: var(--bg-secondary);
    border-color: var(--border-color-hover);
    color: var(--text-primary);
}

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

/* ==========================================================================
   DISCIPLINE CATEGORIES STATIC SECTION
   ========================================================================== */
.disciplines-section {
    background-color: var(--bg-secondary);
    padding: var(--space-6) 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.section-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-3);
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-4);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.section-header h2 {
    font-size: 28px;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    margin-bottom: var(--space-1);
}

.section-header p {
    font-size: 15px;
    color: var(--text-secondary);
}

.discipline-cards-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-2);
}

.discipline-nav-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    padding: var(--space-3);
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    flex-direction: column;
}

.discipline-nav-card:hover {
    border-color: var(--border-color-hover);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.card-icon-wrapper {
    width: 36px;
    height: 36px;
    background-color: var(--primary-color-light);
    color: var(--primary-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-2);
}

.card-icon-wrapper svg {
    width: 20px;
    height: 20px;
}

.discipline-nav-card h3 {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-1);
    line-height: 1.3;
}

.discipline-nav-card p {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: var(--space-2);
    flex-grow: 1;
    line-height: 1.4;
}

.card-link {
    font-size: 13px;
    font-weight: 600;
    color: var(--primary-color);
    display: inline-block;
    transition: transform var(--transition-fast);
}

.discipline-nav-card:hover .card-link {
    transform: translateX(4px);
}

/* ==========================================================================
   CONTACT SECTION
   ========================================================================== */
.contact-section {
    padding: var(--space-6) 0;
    background-color: var(--bg-primary);
}

.contact-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-3);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4);
    align-items: start;
}

.contact-info h2 {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    margin-bottom: var(--space-2);
}

.contact-lead {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: var(--space-4);
    line-height: 1.6;
}

.info-blocks {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    margin-bottom: var(--space-4);
}

.info-block {
    display: flex;
    gap: var(--space-2);
    align-items: flex-start;
}

.info-icon {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-default);
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    border: 1px solid var(--border-color);
}

.info-icon svg {
    width: 20px;
    height: 20px;
}

.info-block h4 {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.info-block p {
    font-size: 14px;
    color: var(--text-secondary);
}

.info-block p a:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

.notice-box {
    padding: var(--space-2);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    font-size: 13px;
    line-height: 1.5;
    color: var(--text-secondary);
}

.notice-badge {
    display: inline-block;
    padding: 2px 6px;
    background-color: var(--text-primary);
    color: var(--bg-primary);
    font-size: 10px;
    font-weight: 700;
    border-radius: var(--radius-sm);
    margin-bottom: 6px;
    text-transform: uppercase;
}

/* Contact Card Form */
.contact-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-4);
    box-shadow: var(--shadow-md);
}

.contact-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: var(--space-3);
    letter-spacing: -0.01em;
}

.form-group {
    margin-bottom: var(--space-2);
    position: relative;
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 10px 14px;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-default);
    font-size: 14px;
    transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--text-primary);
    box-shadow: 0 0 0 2px rgba(15, 23, 42, 0.08);
}

.form-group input.invalid,
.form-group textarea.invalid {
    border-color: var(--danger-color);
}

.form-group input.invalid:focus,
.form-group textarea.invalid:focus {
    box-shadow: 0 0 0 2px rgba(220, 38, 38, 0.1);
}

.error-message {
    display: none;
    font-size: 11px;
    color: var(--danger-color);
    font-weight: 500;
    margin-top: 4px;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.footer {
    background-color: var(--text-primary);
    color: var(--bg-tertiary);
    padding: var(--space-6) 0 var(--space-4) 0;
    font-size: 14px;
}

.footer-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-3);
}

.footer-top {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: var(--space-4);
    margin-bottom: var(--space-4);
}

.footer-brand .logo {
    color: var(--bg-primary);
    margin-bottom: var(--space-2);
}

.footer-brand .logo-icon {
    color: var(--primary-color-light);
}

.footer-description {
    color: var(--text-muted);
    line-height: 1.6;
    max-width: 400px;
}

.footer-nav-group h4 {
    font-size: 13px;
    font-weight: 600;
    color: var(--bg-primary);
    margin-bottom: var(--space-2);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer-nav-group ul {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.footer-nav-group a {
    color: var(--text-muted);
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    border-top: 1px solid #1e293b; /* Slate 800 */
    padding-top: var(--space-3);
    text-align: center;
    color: var(--text-muted);
    font-size: 12px;
}

/* ==========================================================================
   MODAL DIALOG POPUP (Privacy Policy, Terms, etc.)
   ========================================================================== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(15, 23, 42, 0.4);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--space-3);
    animation: fadeIn var(--transition-fast);
}

.modal-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 680px;
    max-height: 80vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    animation: slideUp var(--transition-normal);
}

.modal-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.modal-header h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
}

.btn-close-modal {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

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

.modal-body {
    padding: 24px;
    overflow-y: auto;
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.modal-body h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: var(--space-2);
    margin-bottom: 6px;
}

.modal-body p {
    margin-bottom: var(--space-2);
}

.modal-body p:last-child {
    margin-bottom: 0;
}

.modal-body ul {
    margin-bottom: var(--space-2);
    padding-left: var(--space-2);
    list-style-type: disc;
}

.modal-body li {
    margin-bottom: 4px;
}

.modal-footer {
    padding: 16px 24px;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
}

/* ==========================================================================
   FEEDBACK STATES (Loading, Empty, Toasts)
   ========================================================================== */
/* Loading State */
.loading-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-6) 0;
    gap: var(--space-2);
}

.spinner {
    width: 32px;
    height: 32px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Empty State */
.empty-state {
    text-align: center;
    padding: var(--space-6) 0;
    max-width: 400px;
    margin: 0 auto;
    animation: fadeIn var(--transition-normal);
}

.empty-icon {
    width: 48px;
    height: 48px;
    color: var(--text-muted);
    margin-bottom: var(--space-2);
}

.empty-state h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: var(--space-1);
    color: var(--text-primary);
}

.empty-state p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: var(--space-3);
    line-height: 1.5;
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    bottom: var(--space-4);
    right: var(--space-4);
    z-index: 1100;
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.toast {
    background-color: var(--text-primary);
    color: var(--bg-primary);
    padding: 12px 20px;
    border-radius: var(--radius-default);
    box-shadow: var(--shadow-lg);
    font-size: 14px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: var(--space-2);
    min-width: 280px;
    max-width: 360px;
    transform: translateY(20px);
    opacity: 0;
    animation: slideUp 0.3s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.toast.toast-success {
    background-color: var(--success-color);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.toast.toast-danger {
    background-color: var(--danger-color);
}

@keyframes slideUp {
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* ==========================================================================
   RESPONSIVE DESIGN (Media Queries)
   ========================================================================== */

/* Large Tablets & Small Desktops (992px to 1200px) */
@media (max-width: 1200px) {
    .discipline-cards-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    .footer-top {
        grid-template-columns: 1fr 1fr 1fr;
    }
    .footer-brand {
        grid-column: span 3;
    }
}

/* Tablets (768px to 991px) */
@media (max-width: 991px) {
    .hero-title {
        font-size: 38px;
    }
    .about-grid {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }
    .contact-grid {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }
    .discipline-cards-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .footer-top {
        grid-template-columns: 1fr 1fr;
    }
    .footer-brand {
        grid-column: span 2;
    }
}

/* Mobile Devices (Up to 767px) */
@media (max-width: 767px) {
    /* Variables override */
    :root {
        --header-height: 64px;
        --space-3: 16px;
        --space-4: 24px;
        --space-6: 32px;
    }
    
    .hero-title {
        font-size: 32px;
    }
    .hero-subtitle {
        font-size: 15px;
    }
    .hero-stats {
        flex-direction: column;
        gap: var(--space-1);
        margin-bottom: var(--space-3);
    }
    .stat-number {
        font-size: 24px;
    }
    
    /* Navigation drawer overlay */
    .mobile-nav-toggle {
        display: block;
        z-index: 101;
    }
    
    .nav {
        position: fixed;
        top: 0;
        right: 0;
        width: 280px;
        height: 100vh;
        background-color: var(--bg-primary);
        box-shadow: var(--shadow-lg);
        border-left: 1px solid var(--border-color);
        padding: 80px var(--space-3) var(--space-3) var(--space-3);
        transform: translateX(100%);
        transition: transform var(--transition-normal);
        z-index: 100;
    }
    
    .nav.open {
        transform: translateX(0);
    }
    
    .nav-list {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-3);
    }
    
    .nav-link {
        font-size: 16px;
        width: 100%;
        display: block;
    }
    
    /* Search & Filter Bar stacking */
    .filter-wrapper {
        flex-direction: column;
        align-items: stretch;
        gap: var(--space-1);
    }
    
    .search-box {
        max-width: none;
    }
    
    .select-filters {
        flex-direction: column;
        align-items: stretch;
        gap: var(--space-1);
    }
    
    .select-wrapper select {
        width: 100%;
    }
    
    .btn-clear {
        width: 100%;
        justify-content: center;
    }
    
    /* Accordion adjustments */
    .category-header {
        padding: 16px var(--space-2);
    }
    .category-title-group h3 {
        font-size: 16px;
    }
    .category-content {
        padding: 16px;
    }
    
    /* Horizontal Card collapses to vertical */
    .conference-list-card {
        flex-direction: column;
        align-items: stretch;
        padding: 16px;
        gap: 12px;
    }
    
    .card-action-side {
        width: 100%;
    }
    
    .discipline-cards-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-top {
        grid-template-columns: 1fr;
        gap: var(--space-3);
    }
    
    .footer-brand {
        grid-column: span 1;
    }
    
    .modal-card {
        max-height: 90vh;
    }
}