/* ===================================
   VARIABLES Y CONFIGURACIÓN GLOBAL
   =================================== */
:root {
    /* Colores institucionales USTA */
    --color-primary: #02adb6;     
    --color-secondary: #ef7ba5;   
    --color-accent: #ffeb3b;
    --color-dark: #1a1a1a;
    --color-light: #f8f9fa;
    --color-white: #ffffff;
    --color-gray-100: #f1f3f5;
    --color-gray-200: #e9ecef;
    --color-gray-300: #dee2e6;
    --color-gray-400: #ced4da;
    --color-gray-500: #adb5bd;
    --color-gray-600: #6c757d;
    --color-gray-700: #495057;
    --color-gray-800: #343a40;
    --color-gray-900: #212529;
    
    /* Tipografía */
    --font-primary: 'Montserrat', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-secondary: 'Merriweather', Georgia, serif;
    
    /* Espaciado */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Sombras */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1), 0 2px 4px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1), 0 4px 6px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.15), 0 10px 10px rgba(0, 0, 0, 0.04);
    
    /* Transiciones */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Border radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 20px;
}

/* Reset y estilos base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: var(--font-primary);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-gray-800);
    background-color: var(--color-white);
    overflow-x: hidden;
}

/* ===================================
   TIPOGRAFÍA
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-dark);
    margin-bottom: 1rem;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: 1rem;
}

.lead-text {
    font-size: 1.25rem;
    font-weight: 400;
    line-height: 1.8;
    color: var(--color-gray-700);
}

/* ===================================
   COMPONENTES REUTILIZABLES
   =================================== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.section {
    padding: var(--spacing-xl) 0;
}

.section-light {
    background-color: var(--color-light);
}

.section-white {
    background-color: var(--color-white);
}

.section-dark {
    background-color: var(--color-primary);
    color: var(--color-white);
}

.section-dark h2,
.section-dark h3,
.section-dark h4 {
    color: var(--color-white);
}

.section-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, #004080 100%);
    color: var(--color-white);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.section-tag {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--color-secondary);
    margin-bottom: var(--spacing-sm);
}

.section-dark .section-tag {
    color: var(--color-accent);
}

.section-title {
    font-family: var(--font-secondary);
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.section-divider {
    width: 80px;
    height: 4px;
    background-color: var(--color-secondary);
    margin: 0 auto;
    border-radius: 2px;
}

.section-dark .section-divider {
    background-color: var(--color-accent);
}

/* Botones */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 2rem;
    font-family: var(--font-primary);
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    text-align: center;
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    white-space: nowrap;
}

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

.btn-primary:hover {
    background-color: #a00d24;
    border-color: #a00d24;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

.btn-light {
    background-color: var(--color-white);
    color: var(--color-primary);
    border-color: var(--color-white);
}

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

.btn-large {
    padding: 1.125rem 2.5rem;
    font-size: 1.125rem;
}

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

/* ===================================
   NAVEGACIÓN
   =================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--color-white);
    box-shadow: var(--shadow-md);
    z-index: 1000;
    transition: all var(--transition-base);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    padding-bottom: 1rem;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.logo {
    height: 50px;
    width: auto;
}

.nav-title {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-primary);
    display: none;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--color-primary);
    transition: var(--transition-base);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 0.5rem;
    align-items: center;
}

.nav-link {
    display: block;
    padding: 0.5rem 1rem;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-gray-700);
    text-decoration: none;
    transition: var(--transition-fast);
    border-radius: var(--radius-sm);
}

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

.nav-link.btn-registro {
    background-color: var(--color-secondary);
    color: var(--color-white);
}

.nav-link.btn-registro:hover {
    background-color: #a00d24;
}

/* ===================================
   HERO SECTION
   =================================== */
.hero {
    position: relative;
    background: linear-gradient(135deg, var(--color-primary) 0%, #004080 100%);
    color: var(--color-white);
    padding: 8rem 0 var(--spacing-xl);
    margin-top: 70px;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        radial-gradient(circle at 20% 50%, rgba(253, 185, 19, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(200, 16, 46, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    opacity: 0.5;
}

.hero-content {
    position: relative;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.hero-text {
    z-index: 2;
}

.hero-title {
    font-family: var(--font-secondary);
    font-size: 3rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: var(--spacing-sm);
    color: var(--color-white);
}

.hero-subtitle {
    font-size: 2rem;
    font-weight: 600;
    color: var(--color-accent);
    margin-bottom: var(--spacing-sm);
}

.hero-description {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-md);
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.hero-flayer {
    z-index: 2;
}

.flayer-container {
    position: relative;
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    aspect-ratio: 2/3;
    max-width: 400px;
    margin: 0 auto;
}

.flayer-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: none;
}

.flayer-image[src]:not([src=""]) {
    display: block;
}

.flayer-image[src]:not([src=""]) + .flayer-placeholder {
    display: none;
}

.flayer-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--color-gray-100) 0%, var(--color-gray-200) 100%);
}

.flayer-placeholder svg {
    width: 100%;
    height: 100%;
}

/* ===================================
   CONTENT BOX
   =================================== */
.content-box {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
}

.text-content p {
    text-align: justify;
    color: var(--color-gray-700);
}

/* ===================================
   CARDS
   =================================== */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: var(--spacing-md);
}

.card {
    background-color: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    text-align: center;
    transition: var(--transition-base);
    backdrop-filter: blur(10px);
}

.card:hover {
    background-color: rgba(255, 255, 255, 0.15);
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.card-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--spacing-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-accent);
    color: var(--color-primary);
    border-radius: 50%;
}

.card-icon svg {
    width: 32px;
    height: 32px;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: var(--spacing-sm);
}

.card-text {
    color: rgba(255, 255, 255, 0.9);
    line-height: 1.6;
}

/* ===================================
   METODOLOGÍA
   =================================== */
.methodology-grid {
    display: grid;
    gap: var(--spacing-md);
}

.methodology-item {
    display: flex;
    gap: var(--spacing-md);
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    transition: var(--transition-base);
}

.methodology-item:hover {
    box-shadow: var(--shadow-lg);
    transform: translateX(5px);
}

.methodology-number {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-white);
    background: linear-gradient(135deg, var(--color-secondary), var(--color-primary));
    border-radius: var(--radius-md);
}

.methodology-content h3 {
    font-size: 1.25rem;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
}

.methodology-content p {
    color: var(--color-gray-600);
    margin: 0;
}

/* ===================================
   TIMELINE (CRONOGRAMA)
   =================================== */
.timeline {
    max-width: 900px;
    margin: 0 auto;
}

.timeline-day {
    margin-bottom: var(--spacing-lg);
}

.timeline-day-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 3px solid var(--color-secondary);
}

.timeline-items {
    position: relative;
    padding-left: var(--spacing-md);
}

.timeline-items::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(to bottom, var(--color-primary), var(--color-secondary));
}

.timeline-item {
    position: relative;
    padding-left: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -9px;
    top: 8px;
    width: 15px;
    height: 15px;
    background-color: var(--color-accent);
    border: 3px solid var(--color-white);
    border-radius: 50%;
    box-shadow: var(--shadow-sm);
}

.timeline-time {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--color-white);
    background-color: var(--color-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    margin-bottom: 0.5rem;
}

.timeline-content h4 {
    font-size: 1.125rem;
    color: var(--color-primary);
    margin-bottom: 0.25rem;
}

.timeline-content p {
    color: var(--color-gray-600);
    margin: 0;
}

.note-box {
    background-color: var(--color-gray-100);
    border-left: 4px solid var(--color-accent);
    padding: var(--spacing-sm) var(--spacing-md);
    margin-top: var(--spacing-md);
    border-radius: var(--radius-sm);
}

.note-box p {
    margin: 0;
    color: var(--color-gray-700);
}

/* Observaciones dentro del cronograma */
.schedule-observations {
    background-color: var(--color-gray-100);
    border-left: 4px solid var(--color-accent);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    border-radius: var(--radius-sm);
}

.schedule-observations h5 {
    color: var(--color-primary);
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.observations-list {
    list-style: none;
    margin: 0;
    padding: 0;
}

.observations-list li {
    padding: 0.5rem 0;
    color: var(--color-gray-700);
    border-bottom: 1px solid var(--color-gray-300);
}

.observations-list li:last-child {
    border-bottom: none;
}

/* Tablas de auditorios */
.auditoriums-schedule {
    margin-top: var(--spacing-md);
}

.auditorium-section {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    border-top: 4px solid var(--color-secondary);
}

.auditorium-title {
    color: var(--color-primary);
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.auditorium-moderator {
    color: var(--color-gray-600);
    font-size: 0.9375rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.table-responsive {
    overflow-x: auto;
    margin-top: var(--spacing-sm);
}

.schedule-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
    background-color: var(--color-white);
}

.schedule-table thead {
    background-color: var(--color-primary);
    color: var(--color-white);
}

.schedule-table thead th {
    padding: 0.875rem;
    text-align: left;
    font-weight: 600;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.schedule-table tbody td {
    padding: 0.875rem;
    border: 1px solid var(--color-gray-300);
    color: var(--color-gray-700);
    vertical-align: top;
}

.schedule-table tbody tr:nth-child(even) {
    background-color: var(--color-gray-100);
}

.schedule-table tbody tr:hover {
    background-color: var(--color-gray-200);
}

.schedule-table tbody td:first-child {
    font-weight: 700;
    color: var(--color-secondary);
    text-align: center;
}

.schedule-table tbody td:nth-child(2) {
    font-weight: 600;
    color: var(--color-primary);
    white-space: nowrap;
}

/* ===================================
   OBSERVACIONES
   =================================== */
.observations-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.observation-card {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-base);
    border-top: 4px solid var(--color-secondary);
}

.observation-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-5px);
}

.observation-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.observation-card h3 {
    font-size: 1.125rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.observation-card p {
    color: var(--color-gray-600);
    margin: 0;
    font-size: 0.9375rem;
}

/* ===================================
   COMITÉ ORGANIZADOR
   =================================== */
.committee-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.committee-member {
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    text-align: center;
    transition: var(--transition-base);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.committee-member:hover {
    background-color: rgba(255, 255, 255, 0.15);
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.member-photo {
    position: relative;
    width: 150px;
    height: 150px;
    margin: 0 auto var(--spacing-sm);
    border-radius: 50%;
    overflow: hidden;
    border: 4px solid var(--color-accent);
    background-color: rgba(255, 255, 255, 0.1);
}

.member-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    display: none;
    position: absolute;
    top: 0;
    left: 0;
}

.member-photo img[src]:not([src=""]) {
    display: block;
}

.member-photo img[src]:not([src=""]) + .member-photo-placeholder {
    display: none;
}

.member-photo-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(253, 185, 19, 0.3), rgba(200, 16, 46, 0.3));
}

.member-photo-placeholder svg {
    width: 60%;
    height: 60%;
    color: rgba(255, 255, 255, 0.7);
}

.member-name {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: 0.5rem;
}

.member-role {
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-accent);
    margin-bottom: 0.5rem;
}

.member-description {
    font-size: 0.9375rem;
    color: rgba(255, 255, 255, 0.8);
    margin: 0;
}

/* ===================================
   REGISTRO
   =================================== */
.registration-box {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: var(--spacing-lg);
    align-items: center;
    max-width: 1000px;
    margin: 0 auto;
}

.registration-content {
    color: var(--color-white);
}

.registration-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: var(--spacing-sm);
}

.registration-text {
    font-size: 1.125rem;
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
    color: rgba(255, 255, 255, 0.9);
}

.registration-benefits {
    list-style: none;
    margin-bottom: var(--spacing-md);
}

.registration-benefits li {
    font-size: 1.125rem;
    padding: 0.5rem 0;
    color: var(--color-white);
}

.registration-note {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.8);
    margin-top: var(--spacing-sm);
    font-style: italic;
}

.registration-image svg {
    width: 100%;
    height: auto;
    opacity: 0.3;
}

/* ===================================
   FOOTER
   =================================== */
.footer {
    background-color: var(--color-dark);
    color: var(--color-gray-300);
    padding: var(--spacing-lg) 0 var(--spacing-md);
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--color-gray-700);
}

.footer-logo {
    height: 60px;
    width: auto;
    margin-bottom: var(--spacing-sm);
    display: none;
}

.footer-logo[src]:not([src=""]) {
    display: block;
}

.footer-logo[src]:not([src=""]) ~ .footer-logo-placeholder {
    display: none;
}

.footer-logo-placeholder h3 {
    color: var(--color-white);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.footer-text {
    color: var(--color-gray-400);
    line-height: 1.8;
}

.footer-title {
    color: var(--color-white);
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.footer-list {
    list-style: none;
}

.footer-list li {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    margin-bottom: 0.75rem;
    color: var(--color-gray-400);
}

.footer-list li svg {
    flex-shrink: 0;
    margin-top: 0.25rem;
    color: var(--color-accent);
}

.footer-list a {
    color: var(--color-gray-400);
    text-decoration: none;
    transition: var(--transition-fast);
}

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

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: var(--color-gray-800);
    color: var(--color-white);
    border-radius: 50%;
    transition: var(--transition-base);
}

.social-links a:hover {
    background-color: var(--color-secondary);
    transform: translateY(-3px);
}

.social-links svg {
    width: 20px;
    height: 20px;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
}

.footer-bottom p {
    color: var(--color-gray-500);
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
}

.footer-credit {
    color: var(--color-gray-600);
    font-size: 0.8125rem;
}

/* ===================================
   SCROLL TO TOP BUTTON
   =================================== */
.scroll-top-btn {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background-color: var(--color-secondary);
    color: var(--color-white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    z-index: 999;
}

.scroll-top-btn.visible {
    opacity: 1;
    visibility: visible;
}

.scroll-top-btn:hover {
    background-color: var(--color-primary);
    transform: translateY(-5px);
}

.scroll-top-btn svg {
    width: 24px;
    height: 24px;
}

/* ===================================
   RESPONSIVE DESIGN
   =================================== */

/* Tablet (768px - 1023px) */
@media (max-width: 1023px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.75rem;
    }
    
    .flayer-container {
        max-width: 350px;
    }
    
    .registration-box {
        grid-template-columns: 1fr;
    }
    
    .registration-image {
        display: none;
    }
    
    .nav-title {
        display: block;
        font-size: 0.875rem;
    }
    
    /* Tablas responsive en tablet */
    .schedule-table {
        font-size: 0.875rem;
    }
    
    .schedule-table thead th,
    .schedule-table tbody td {
        padding: 0.75rem 0.5rem;
    }
}

/* Mobile (menos de 768px) */
@media (max-width: 767px) {
    :root {
        --spacing-md: 1.5rem;
        --spacing-lg: 2.5rem;
        --spacing-xl: 3rem;
    }
    
    html {
        font-size: 14px;
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .section {
        padding: var(--spacing-lg) 0;
    }
    
    /* Navegación móvil */
    .nav-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background-color: var(--color-white);
        flex-direction: column;
        align-items: stretch;
        padding: var(--spacing-md);
        gap: 0;
        box-shadow: var(--shadow-lg);
        transition: left var(--transition-base);
        overflow-y: auto;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-link {
        padding: 1rem;
        border-bottom: 1px solid var(--color-gray-200);
    }
    
    /* Hero */
    .hero {
        padding: 6rem 0 var(--spacing-lg);
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.5rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .flayer-container {
        max-width: 300px;
    }
    
    /* Secciones */
    .section-title {
        font-size: 1.75rem;
    }
    
    .cards-grid {
        grid-template-columns: 1fr;
    }
    
    .methodology-item {
        flex-direction: column;
        text-align: center;
    }
    
    .methodology-number {
        margin: 0 auto;
    }
    
    .timeline-items {
        padding-left: var(--spacing-sm);
    }
    
    .timeline-item {
        padding-left: var(--spacing-sm);
    }
    
    .observations-grid,
    .committee-grid {
        grid-template-columns: 1fr;
    }
    
    .registration-title {
        font-size: 2rem;
    }
    
    .registration-text {
        font-size: 1rem;
    }
    
    .registration-benefits li {
        font-size: 1rem;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
    }
    
    .scroll-top-btn {
        bottom: 1rem;
        right: 1rem;
        width: 45px;
        height: 45px;
    }
    
    /* Tablas responsive en móvil */
    .schedule-table {
        font-size: 0.8125rem;
    }
    
    .schedule-table thead th,
    .schedule-table tbody td {
        padding: 0.5rem 0.375rem;
    }
    
    /* Ocultar algunas columnas en móviles muy pequeños */
    .auditorium-section {
        padding: var(--spacing-sm);
    }
    
    .auditorium-title {
        font-size: 1rem;
    }
    
    .schedule-observations {
        padding: var(--spacing-sm);
    }
    
    .observations-list li {
        font-size: 0.875rem;
    }
}

/* Muy pequeño (menos de 480px) */
@media (max-width: 479px) {
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
    
    .btn-large {
        padding: 1rem 2rem;
        font-size: 1rem;
    }
    
    /* Tablas muy compactas en pantallas muy pequeñas */
    .schedule-table thead th:nth-child(3) {
        display: none; /* Ocultar área de conocimiento en pantallas muy pequeñas */
    }
    
    .schedule-table tbody td:nth-child(3) {
        display: none;
    }
}

/* Animaciones */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* Aplicar animaciones con scroll (se activará vía JavaScript) */
.animate-on-scroll {
    opacity: 0;
    animation: fadeInUp 0.8s ease forwards;
}

/* Print styles */
@media print {
    .navbar,
    .nav-toggle,
    .hero-buttons,
    .scroll-top-btn,
    .social-links {
        display: none !important;
    }
    
    .section {
        page-break-inside: avoid;
    }
}