/**
 * Congress Template - Main Stylesheet
 * 
 * Organized native CSS with semantic classes
 * No external dependencies - fully self-contained
 * 
 * @package CongressTemplate
 * @version 2.0.0
 */

/* ==========================================================================
   1. CSS Variables & Branding
   ========================================================================== */

:root {
    /* Spacing Scale */
    --spacing-xs: 0.25rem;    /* 4px */
    --spacing-sm: 0.5rem;     /* 8px */
    --spacing-md: 1rem;       /* 16px */
    --spacing-lg: 1.5rem;     /* 24px */
    --spacing-xl: 2rem;       /* 32px */
    --spacing-2xl: 3rem;      /* 48px */
    --spacing-3xl: 4rem;      /* 64px */
    --spacing-4xl: 5rem;      /* 80px */
    
    /* Typography Scale */
    --font-size-xs: 0.75rem;   /* 12px */
    --font-size-sm: 0.875rem;  /* 14px */
    --font-size-base: 1rem;    /* 16px */
    --font-size-lg: 1.125rem;  /* 18px */
    --font-size-xl: 1.25rem;   /* 20px */
    --font-size-2xl: 1.5rem;   /* 24px */
    --font-size-3xl: 1.875rem; /* 30px */
    --font-size-4xl: 2.25rem;  /* 36px */
    --font-size-5xl: 3rem;     /* 48px */
    --font-size-6xl: 3.75rem;  /* 60px */
    --font-size-7xl: 4.5rem;   /* 72px */
    
    /* Font Weights */
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    /* Line Heights */
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;
    
    /* Border Radius */
    --radius-sm: 0.25rem;   /* 4px */
    --radius-md: 0.5rem;    /* 8px */
    --radius-lg: 0.75rem;   /* 12px */
    --radius-xl: 1rem;      /* 16px */
    --radius-2xl: 1.5rem;   /* 24px */
    --radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    
    /* Colors - Default (overridden by dynamic branding) */
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;
    
    /* Dynamic Branding Colors (injected via functions.php) */
    --primary: #0073aa;
    --secondary: #005a87;
    --primary-rgb: 0, 115, 170;
    --secondary-rgb: 0, 88, 135;
    --congress-primary-color: #0073aa;
    --congress-secondary-color: #005a87;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
    --transition-slow: 500ms ease;
    
    /* Z-index Scale */
    --z-base: 1;
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* ==========================================================================
   2. Reset & Base
   ========================================================================== */

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

html {
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-gray-900);
    background-color: #fff;
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: var(--font-weight-bold);
    line-height: var(--line-height-tight);
    color: var(--color-gray-900);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
    margin-bottom: var(--spacing-md);
}

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

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

a:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

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

/* ==========================================================================
   3. Layout
   ========================================================================== */

/* Container System */
.container {
    width: 100%;
    max-width: 1200px;
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--spacing-md);
    padding-right: var(--spacing-md);
}

@media (min-width: 475px) {
    .container {
        padding-left: var(--spacing-lg);
        padding-right: var(--spacing-lg);
    }
}

@media (min-width: 1024px) {
    .container {
        padding-left: var(--spacing-xl);
        padding-right: var(--spacing-xl);
    }
}

/* Site Structure */
.site {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.site-content {
    flex: 1;
}

/* Grid System */
.grid {
    display: grid;
    gap: var(--spacing-lg);
}

.grid--2cols {
    grid-template-columns: 1fr;
}

.grid--3cols {
    grid-template-columns: 1fr;
}

.grid--4cols {
    grid-template-columns: 1fr;
}

@media (min-width: 768px) {
    .grid--2cols {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .grid--3cols {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .grid--4cols {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* Flexbox Utilities */
.flex-row {
    display: flex;
    flex-direction: row;
}

.flex-col {
    display: flex;
    flex-direction: column;
}

.flex-center {
    align-items: center;
    justify-content: center;
}

.flex-between {
    justify-content: space-between;
}

.flex-start {
    align-items: flex-start;
}

.flex-wrap {
    flex-wrap: wrap;
}

.flex-nowrap {
    flex-wrap: nowrap;
}

/* Spacing System */
.section-spacing {
    padding-top: var(--spacing-2xl);
    padding-bottom: var(--spacing-2xl);
}

.section-spacing--large {
    padding-top: var(--spacing-3xl);
    padding-bottom: var(--spacing-3xl);
}

@media (min-width: 1024px) {
    .section-spacing--large {
        padding-top: var(--spacing-4xl);
        padding-bottom: var(--spacing-4xl);
    }
}

/* ==========================================================================
   4. Components
   ========================================================================== */

/* Buttons */
.btn-primary,
.btn-register,
.button {
    display: inline-block;
    padding: var(--spacing-md) var(--spacing-xl);
    background-color: var(--primary);
    color: #fff;
    font-weight: var(--font-weight-semibold);
    font-size: var(--font-size-base);
    text-align: center;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    text-decoration: none;
    transition: background-color var(--transition-base), transform var(--transition-fast), box-shadow var(--transition-base);
}

.btn-primary:hover,
.btn-register:hover,
.button:hover {
    background-color: var(--secondary);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-primary:focus-visible,
.btn-register:focus-visible,
.button:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

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

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

.btn-cta {
    background-color: #fff;
    color: var(--primary);
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-bold);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-2xl);
}

.btn-cta:hover {
    background-color: rgba(255, 255, 255, 0.9);
    color: var(--secondary);
    transform: scale(1.05);
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.2);
}

.btn-register-large {
    padding: var(--spacing-lg) var(--spacing-3xl);
    font-size: var(--font-size-xl);
}

/* Cards */
.card {
    background-color: #fff;
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-gray-200);
    transition: box-shadow var(--transition-base), transform var(--transition-fast);
}

.card:hover {
    box-shadow: var(--shadow-xl);
    transform: translateY(-2px);
}

.card--large {
    padding: var(--spacing-2xl);
}

.card-hero {
    background-color: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-xl);
}

.card-info {
    text-align: center;
}

.card-venue {
    background-color: #fff;
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
}

/* Navigation */
.nav-primary {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
    list-style: none;
}

.nav-primary a {
    color: var(--color-gray-700);
    font-weight: var(--font-weight-medium);
    padding: var(--spacing-sm) 0;
    transition: color var(--transition-fast);
}

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

.nav-mobile {
    display: none;
    flex-direction: column;
    gap: var(--spacing-sm);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-gray-200);
    margin-top: var(--spacing-md);
}

.nav-mobile--open {
    display: flex;
}

.nav-mobile a {
    display: block;
    padding: var(--spacing-md);
    color: var(--color-gray-700);
    border-radius: var(--radius-md);
    transition: background-color var(--transition-fast), color var(--transition-fast);
}

.nav-mobile a:hover {
    background-color: var(--color-gray-50);
    color: var(--primary);
}

.nav-toggle {
    display: flex;
    padding: var(--spacing-sm);
    border-radius: var(--radius-md);
    background: transparent;
    border: none;
    color: var(--color-gray-700);
    cursor: pointer;
    transition: background-color var(--transition-fast), color var(--transition-fast);
}

.nav-toggle:hover {
    background-color: var(--color-gray-100);
    color: var(--primary);
}

.nav-toggle:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

@media (min-width: 768px) {
    .nav-mobile {
        display: none !important;
    }
    
    .nav-toggle {
        display: none;
    }
}

/* Icons */
.icon-wrapper {
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.icon-small {
    width: 1.25rem;
    height: 1.25rem;
}

.icon-medium {
    width: 2rem;
    height: 2rem;
}

.icon-large {
    width: 3rem;
    height: 3rem;
}

/* Loading States */
.skeleton {
    background: linear-gradient(90deg, var(--color-gray-200) 25%, var(--color-gray-100) 50%, var(--color-gray-200) 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s ease-in-out infinite;
    border-radius: var(--radius-md);
}

@keyframes skeleton-loading {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}

.skeleton-text {
    height: 1rem;
    margin-bottom: var(--spacing-sm);
}

.skeleton-title {
    height: 2rem;
    margin-bottom: var(--spacing-md);
}

.spinner {
    display: inline-block;
    width: 1.5rem;
    height: 1.5rem;
    border: 2px solid var(--color-gray-200);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spinner-rotate 0.6s linear infinite;
}

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

/* ==========================================================================
   5. Templates
   ========================================================================== */

/* Header */
.site-header {
    background-color: #fff;
    border-bottom: 1px solid var(--color-gray-200);
    padding: var(--spacing-md) 0;
}

.site-header--sticky {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    box-shadow: var(--shadow-sm);
}

.header-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 4rem;
}

@media (min-width: 1024px) {
    .header-nav {
        height: 5rem;
    }
}

.site-branding {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.site-logo {
    flex-shrink: 0;
}

.logo-image {
    height: 2.5rem;
    width: auto;
    object-fit: contain;
}

@media (min-width: 1024px) {
    .logo-image {
        height: 3rem;
    }
}

.site-title {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-bold);
    color: var(--color-gray-900);
    line-height: var(--line-height-tight);
    margin: 0;
}

@media (min-width: 1024px) {
    .site-title {
        font-size: var(--font-size-xl);
    }
}

.site-description {
    font-size: var(--font-size-xs);
    color: var(--color-gray-600);
    line-height: var(--line-height-normal);
    margin: 0;
    display: none;
}

@media (min-width: 475px) {
    .site-description {
        display: block;
    }
}

/* Footer */
.site-footer {
    background-color: var(--color-gray-900);
    color: var(--color-gray-300);
    padding: var(--spacing-2xl) 0;
    margin-top: var(--spacing-4xl);
}

.footer-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

@media (min-width: 768px) {
    .footer-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.footer-section h3,
.footer-section h4 {
    color: #fff;
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-md);
}

.footer-section p {
    font-size: var(--font-size-sm);
    color: var(--color-gray-400);
    margin-bottom: var(--spacing-sm);
}

.footer-link {
    color: var(--color-gray-400);
    transition: color var(--transition-fast);
}

.footer-link:hover {
    color: #fff;
}

.footer-section__list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

/* Hero Section */
.hero-section {
    position: relative;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: #fff;
    padding: var(--spacing-4xl) var(--spacing-md);
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    inset: 0;
    opacity: 0.1;
    background-image: radial-gradient(circle at 2px 2px, white 1px, transparent 0);
    background-size: 40px 40px;
}

@media (min-width: 1024px) {
    .hero-section {
        padding: var(--spacing-4xl) var(--spacing-xl);
    }
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
    position: relative;
    z-index: var(--z-base);
}

@media (min-width: 1024px) {
    .hero-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-4xl);
    }
}

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: var(--font-weight-bold);
    line-height: var(--line-height-tight);
    margin-bottom: var(--spacing-lg);
    color: #fff;
    text-align: center;
}

@media (min-width: 475px) {
    .hero-title {
        font-size: var(--font-size-5xl);
    }
}

@media (min-width: 1024px) {
    .hero-title {
        font-size: var(--font-size-6xl);
        text-align: left;
    }
}

@media (min-width: 1280px) {
    .hero-title {
        font-size: var(--font-size-7xl);
    }
}

.hero-description {
    font-size: var(--font-size-lg);
    line-height: var(--line-height-relaxed);
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

@media (min-width: 475px) {
    .hero-description {
        font-size: var(--font-size-xl);
    }
}

@media (min-width: 1024px) {
    .hero-description {
        font-size: var(--font-size-2xl);
        text-align: left;
    }
}

.hero-card {
    background-color: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-xl);
    margin-bottom: var(--spacing-lg);
}

.hero-card__content {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
}

.hero-card__icon {
    flex-shrink: 0;
    color: #fff;
}

.hero-card__text h3 {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: var(--spacing-xs);
}

.hero-card__text p {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    color: #fff;
    margin: 0;
}

.hero-card__text .text-muted {
    display: block;
    font-size: var(--font-size-lg);
    color: rgba(255, 255, 255, 0.9);
    margin-top: var(--spacing-xs);
}

/* Info Cards Section */
.info-cards-section {
    padding: var(--spacing-2xl) 0;
    background-color: #fff;
}

@media (min-width: 1024px) {
    .info-cards-section {
        padding: var(--spacing-3xl) 0;
    }
}

.info-cards-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

@media (min-width: 768px) {
    .info-cards-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.info-card {
    background-color: #fff;
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-gray-200);
    text-align: center;
    transition: box-shadow var(--transition-base);
}

.info-card:hover {
    box-shadow: var(--shadow-xl);
}

.info-card__icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 4rem;
    height: 4rem;
    background-color: rgba(var(--primary-rgb), 0.1);
    border-radius: var(--radius-xl);
    margin: 0 auto var(--spacing-lg);
}

.info-card__icon svg {
    width: 2rem;
    height: 2rem;
    color: var(--primary);
}

.info-card h3 {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-gray-900);
    margin-bottom: var(--spacing-md);
}

.info-card p {
    color: var(--color-gray-600);
    margin: 0;
}

.info-card--gradient {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: #fff;
}

.info-card--gradient h3,
.info-card--gradient p {
    color: #fff;
}

.info-card--gradient .info-card__icon {
    background-color: rgba(255, 255, 255, 0.2);
}

.info-card--gradient .info-card__icon svg {
    color: #fff;
}

/* Venue Section */
.venue-section {
    padding: var(--spacing-2xl) 0;
    background-color: var(--color-gray-50);
}

@media (min-width: 1024px) {
    .venue-section {
        padding: var(--spacing-3xl) 0;
    }
}

.venue-card {
    background-color: #fff;
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-gray-200);
}

.venue-card__header {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-lg);
}

.venue-card__icon {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 4rem;
    height: 4rem;
    background-color: rgba(var(--primary-rgb), 0.1);
    border-radius: var(--radius-xl);
}

.venue-card__icon svg {
    width: 2rem;
    height: 2rem;
    color: var(--primary);
}

.venue-card__content h3 {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-gray-900);
    margin-bottom: var(--spacing-md);
}

.venue-card__content p {
    color: var(--color-gray-700);
    margin-bottom: var(--spacing-sm);
}

.venue-card__content .venue-name {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
}

.venue-card__content .venue-address {
    color: var(--color-gray-600);
}

.venue-card__map {
    margin-top: var(--spacing-lg);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.venue-card__map iframe {
    width: 100%;
    height: 300px;
    border: 0;
}

/* CTA Section */
.cta-section {
    padding: var(--spacing-2xl) 0;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: #fff;
    text-align: center;
}

@media (min-width: 1024px) {
    .cta-section {
        padding: var(--spacing-3xl) 0;
    }
}

.cta-section h2 {
    font-size: var(--font-size-3xl);
    color: #fff;
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 1024px) {
    .cta-section h2 {
        font-size: var(--font-size-4xl);
    }
}

.cta-section p {
    font-size: var(--font-size-xl);
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-xl);
}

/* Sticky CTA */
.sticky-cta {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: var(--z-fixed);
    display: none;
}

@media (min-width: 1024px) {
    .sticky-cta {
        display: block;
    }
}

.sticky-cta__button {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    background-color: var(--primary);
    color: #fff;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-full);
    font-weight: var(--font-weight-bold);
    box-shadow: var(--shadow-2xl);
    transition: background-color var(--transition-base), transform var(--transition-fast);
    text-decoration: none;
}

.sticky-cta__button:hover {
    background-color: var(--secondary);
    transform: scale(1.05);
}

.sticky-cta__button:focus-visible {
    outline: 2px solid #fff;
    outline-offset: 2px;
}

/* About Section */
.about-section {
    padding: var(--spacing-2xl) 0;
    background-color: var(--color-gray-50);
}

@media (min-width: 1024px) {
    .about-section {
        padding: var(--spacing-3xl) 0;
    }
}

.about-section h2 {
    font-size: var(--font-size-3xl);
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

@media (min-width: 1024px) {
    .about-section h2 {
        font-size: var(--font-size-4xl);
    }
}

.about-section p {
    font-size: var(--font-size-lg);
    line-height: var(--line-height-relaxed);
    color: var(--color-gray-700);
    max-width: 64rem;
    margin-left: auto;
    margin-right: auto;
}

/* Page Templates */
.page-header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
    padding-bottom: var(--spacing-xl);
    border-bottom: 2px solid var(--color-gray-200);
}

.page-title {
    font-size: var(--font-size-3xl);
    margin-bottom: var(--spacing-sm);
    color: var(--color-gray-900);
}

.page-subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-gray-600);
}

.page-intro {
    margin-bottom: var(--spacing-xl);
    font-size: var(--font-size-lg);
    line-height: var(--line-height-relaxed);
}

/* Registration Page */
.congress-registration-page {
    padding: var(--spacing-xl) 0;
}

.registration-content {
    max-width: 50rem;
    margin: 0 auto;
}

.congress-info {
    background-color: var(--color-gray-50);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-xl);
}

.congress-description {
    line-height: var(--line-height-relaxed);
}

.congress-dates,
.congress-venue {
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background-color: var(--color-gray-100);
    border-left: 4px solid var(--primary);
    border-radius: var(--radius-md);
}

.congress-dates h3,
.congress-venue h3 {
    margin-bottom: var(--spacing-sm);
    color: var(--primary);
    font-size: var(--font-size-xl);
}

.registration-cta {
    text-align: center;
    padding: var(--spacing-3xl) var(--spacing-xl);
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: #fff;
    border-radius: var(--radius-lg);
    margin: var(--spacing-3xl) 0;
}

.registration-cta h2 {
    color: #fff;
    margin-bottom: var(--spacing-md);
}

.registration-cta p {
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-xl);
    font-size: var(--font-size-lg);
}

/* Contact Page */
.congress-contact-page {
    padding: var(--spacing-xl) 0;
}

.contact-info-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

@media (min-width: 768px) {
    .contact-info-grid {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    }
}

.contact-section {
    padding: var(--spacing-xl);
    background-color: var(--color-gray-50);
    border-radius: var(--radius-lg);
}

.contact-section h2 {
    margin-bottom: var(--spacing-md);
    color: var(--primary);
    font-size: var(--font-size-xl);
}

.venue-info p {
    margin-bottom: var(--spacing-sm);
}

.venue-name {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
}

.venue-address {
    color: var(--color-gray-600);
}

.venue-location {
    color: var(--color-gray-600);
    font-style: italic;
}

.contact-details p {
    margin-bottom: var(--spacing-md);
}

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

.contact-details a:hover {
    text-decoration: underline;
}

/* ==========================================================================
   6. Utilities
   ========================================================================== */

/* Text Utilities */
.text-center {
    text-align: center;
}

.text-left {
    text-align: left;
}

.text-right {
    text-align: right;
}

.text-muted {
    color: var(--color-gray-600);
}

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

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

.text-white {
    color: #fff;
}

/* Display Utilities */
.display-block {
    display: block;
}

.display-inline-block {
    display: inline-block;
}

.display-flex {
    display: flex;
}

.display-grid {
    display: grid;
}

.display-none {
    display: none;
}

/* Visibility Utilities */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.show-mobile {
    display: block;
}

.hide-mobile {
    display: none;
}

@media (min-width: 768px) {
    .show-mobile {
        display: none;
    }
    
    .hide-mobile {
        display: block;
    }
}

.show-tablet {
    display: none;
}

@media (min-width: 768px) and (max-width: 1023px) {
    .show-tablet {
        display: block;
    }
}

.hide-tablet {
    display: block;
}

@media (min-width: 768px) and (max-width: 1023px) {
    .hide-tablet {
        display: none;
    }
}

.show-desktop {
    display: none;
}

@media (min-width: 1024px) {
    .show-desktop {
        display: block;
    }
}

.hide-desktop {
    display: block;
}

@media (min-width: 1024px) {
    .hide-desktop {
        display: none;
    }
}

/* Background Utilities */
.bg-primary {
    background-color: var(--primary);
}

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

.bg-gradient-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
}

.bg-white {
    background-color: #fff;
}

.bg-gray-50 {
    background-color: var(--color-gray-50);
}

/* ==========================================================================
   7. Responsive Design
   ========================================================================== */

/* Mobile First - Base styles are for mobile (320px+) */

/* Extra Small Devices (475px+) */
@media (min-width: 475px) {
    .container {
        padding-left: var(--spacing-lg);
        padding-right: var(--spacing-lg);
    }
}

/* Tablets (768px+) */
@media (min-width: 768px) {
    .site-title {
        font-size: var(--font-size-xl);
    }
    
    .entry-title {
        font-size: var(--font-size-3xl);
    }
    
    .page-title {
        font-size: var(--font-size-3xl);
    }
    
    .hero-title {
        font-size: var(--font-size-5xl);
    }
    
    .hero-description {
        font-size: var(--font-size-xl);
    }
    
    .contact-info-grid {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    }
    
    .congress-highlights {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }
    
    .main-navigation ul {
        flex-direction: row;
    }
    
    .registration-cta {
        padding: var(--spacing-3xl) var(--spacing-xl);
    }
    
    .btn-register-large {
        padding: var(--spacing-lg) var(--spacing-2xl);
        font-size: var(--font-size-lg);
    }
}

/* Desktops (1024px+) */
@media (min-width: 1024px) {
    .container {
        padding-left: var(--spacing-xl);
        padding-right: var(--spacing-xl);
    }
    
    .hero-title {
        font-size: var(--font-size-6xl);
    }
    
    .hero-description {
        font-size: var(--font-size-2xl);
    }
}

/* Large Desktops (1280px+) */
@media (min-width: 1280px) {
    .hero-title {
        font-size: var(--font-size-7xl);
    }
}

/* Extra Large Screens (1920px+) */
@media (min-width: 1920px) {
    .container {
        max-width: 1400px;
    }
}

/* ==========================================================================
   8. Accessibility & Animations
   ========================================================================== */

/* Focus Styles */
*:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

button:focus-visible,
a:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    
    .skeleton {
        animation: none;
    }
    
    .spinner {
        animation: none;
    }
}

/* Smooth Transitions */
.transition-fast {
    transition: all var(--transition-fast);
}

.transition-base {
    transition: all var(--transition-base);
}

.transition-slow {
    transition: all var(--transition-slow);
}

/* Fade In Animation */
@keyframes fade-in {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-fade-in {
    animation: fade-in 0.3s ease-out;
}

@media (prefers-reduced-motion: reduce) {
    .animate-fade-in {
        animation: none;
    }
}

/* ARIA-friendly styles */
[aria-hidden="true"] {
    display: none;
}

[aria-label] {
    cursor: pointer;
}

/* Skip to content link */
.skip-to-content {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary);
    color: #fff;
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    z-index: var(--z-tooltip);
}

.skip-to-content:focus {
    top: 0;
}