/* ================================================================
   Academia 5.000 Millas — Obsidiana + Oro Sagrado
   Método BDL: ⛵ + 💎 = 🦁
   ================================================================ */

@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;700&family=Outfit:wght@300;400;500;600;700&family=Playfair+Display:ital,wght@0,400;0,500;0,600;0,700;1,400;1,500&display=swap');

/* ── Variables ── */
:root {
  --obsidiana: #0A0A0A;
  --obsidiana-light: #111111;
  --obsidiana-lighter: #1A1A1A;
  --obsidiana-card: #141414;
  --oro: #D4A574;
  --oro-light: #E8C9A0;
  --oro-dark: #B8895A;
  --oro-subtle: rgba(212, 165, 116, 0.08);
  --oro-glow: rgba(212, 165, 116, 0.15);
  --blanco: #F5F0EB;
  --blanco-soft: rgba(245, 240, 235, 0.85);
  --blanco-muted: rgba(245, 240, 235, 0.5);
  --gris: #888888;
  --gris-dark: #333333;
  --border: rgba(212, 165, 116, 0.12);
  --border-hover: rgba(212, 165, 116, 0.35);
  --barco: #4A90D9;
  --diamante: #D4A574;
  --leon: #C0392B;
  --font-display: 'Playfair Display', Georgia, serif;
  --font-body: 'Outfit', -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --radius: 2px;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.6);
  --shadow-oro: 0 4px 20px rgba(212, 165, 116, 0.1);
  --header-h: 72px;
  --max-w: 1200px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scrollbar-color: var(--gris-dark) var(--obsidiana);
}

::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: var(--obsidiana);
}

::-webkit-scrollbar-thumb {
  background: var(--gris-dark);
  border-radius: var(--radius);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--oro-dark);
}

body {
  font-family: var(--font-body);
  background-color: var(--obsidiana);
  background-image: radial-gradient(ellipse at 50% 0%, rgba(212, 165, 116, 0.03) 0%, transparent 70%);
  color: var(--blanco);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  font-weight: 300;
}

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

a:hover {
  color: var(--oro-light);
}

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

/* ── Utilidades ── */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 1.5rem;
}

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

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

.font-display {
  font-family: var(--font-display);
}

.font-mono {
  font-family: var(--font-mono);
}

/* ── Header ── */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-h);
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.header-logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--blanco);
  letter-spacing: -0.01em;
}

.header-logo:hover {
  color: var(--blanco);
}

.header-badge {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--oro);
  border: 1px solid var(--oro);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.header-nav a {
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--blanco-muted);
  transition: color var(--transition);
  position: relative;
}

.header-nav a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--oro);
  transition: width var(--transition);
}

.header-nav a:hover,
.header-nav a.active {
  color: var(--oro);
}

.header-nav a:hover::after,
.header-nav a.active::after {
  width: 100%;
}

.header-nav-external {
  font-family: var(--font-mono);
  font-size: 0.75rem !important;
  letter-spacing: 0.05em;
  opacity: 0.6;
}

.header-nav-external:hover {
  opacity: 1;
}

/* ── Hamburguesa (móvil) ── */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  background: none;
  border: none;
  z-index: 1001;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 1.5px;
  background: var(--blanco);
  transition: transform var(--transition), opacity var(--transition);
}

.hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translate(4px, 5px);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(4px, -5px);
}

/* ── Botones ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8rem 1.75rem;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 500;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition);
  border: none;
  text-decoration: none;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

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

.btn-primary:hover {
  background: var(--oro-light);
  color: var(--obsidiana);
  box-shadow: var(--shadow-oro);
}

.btn-outline {
  background: transparent;
  color: var(--blanco);
  border: 1px solid var(--border);
}

.btn-outline:hover {
  border-color: var(--oro);
  color: var(--oro);
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.8rem;
}

.btn-lg {
  padding: 1rem 2.5rem;
  font-size: 1rem;
}

/* ── Badges ── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius);
  border: 1px solid;
}

.badge-barco {
  color: var(--barco);
  border-color: rgba(74, 144, 217, 0.3);
  background: rgba(74, 144, 217, 0.08);
}

.badge-diamante {
  color: var(--diamante);
  border-color: rgba(212, 165, 116, 0.3);
  background: rgba(212, 165, 116, 0.08);
}

.badge-leon {
  color: var(--leon);
  border-color: rgba(192, 57, 43, 0.3);
  background: rgba(192, 57, 43, 0.08);
}

.badge-gratis {
  color: #27ae60;
  border-color: rgba(39, 174, 96, 0.3);
  background: rgba(39, 174, 96, 0.08);
}

.badge-premium {
  color: var(--oro);
  border-color: rgba(212, 165, 116, 0.3);
  background: rgba(212, 165, 116, 0.08);
}

.badge-proximamente {
  color: var(--gris);
  border-color: rgba(136, 136, 136, 0.3);
  background: rgba(136, 136, 136, 0.08);
}

/* ── Hero ── */
.hero {
  min-height: 90vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--header-h) + 4rem) 1.5rem 4rem;
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(212, 165, 116, 0.06) 0%, transparent 70%);
  pointer-events: none;
}

.hero-badge {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--oro);
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 600;
  line-height: 1.1;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.hero-ecuacion {
  font-size: 1.75rem;
  margin-bottom: 1rem;
  letter-spacing: 0.3em;
}

.hero-subtitulo {
  font-size: 1.1rem;
  color: var(--blanco-muted);
  max-width: 540px;
  margin: 0 auto 2.5rem;
  font-weight: 300;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  margin-bottom: 3rem;
  flex-wrap: wrap;
}

.hero-stats {
  display: flex;
  gap: 3rem;
  justify-content: center;
  flex-wrap: wrap;
}

.hero-stat {
  text-align: center;
}

.hero-stat-number {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--oro);
  display: block;
}

.hero-stat-label {
  font-size: 0.75rem;
  color: var(--blanco-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* ── Secciones ── */
.section {
  padding: 5rem 0;
}

.section-header {
  text-align: center;
  margin-bottom: 3rem;
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--oro);
  margin-bottom: 0.75rem;
  display: block;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 600;
  letter-spacing: -0.01em;
}

.section-subtitle {
  color: var(--blanco-muted);
  margin-top: 0.75rem;
  font-weight: 300;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ── Cards de categoría ── */
.categorias-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.categoria-card {
  background: var(--obsidiana-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2.5rem 2rem;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  color: var(--blanco);
  display: block;
}

.categoria-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  color: var(--blanco);
  text-decoration: none;
}

.categoria-emoji {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  display: block;
}

.categoria-nombre {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.categoria-subtitulo {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--oro);
  margin-bottom: 0.75rem;
}

.categoria-descripcion {
  font-size: 0.9rem;
  color: var(--blanco-muted);
  font-weight: 300;
  line-height: 1.6;
}

/* ── Cards de curso ── */
.cursos-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.curso-card {
  background: var(--obsidiana-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
  cursor: pointer;
  text-decoration: none;
  color: var(--blanco);
  display: block;
}

.curso-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  color: var(--blanco);
  text-decoration: none;
}

.curso-card-thumb {
  aspect-ratio: 16 / 9;
  background: var(--obsidiana-lighter);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.curso-card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.curso-card-thumb-placeholder {
  font-size: 3rem;
  opacity: 0.3;
}

.curso-card-body {
  padding: 1.25rem;
}

.curso-card-badges {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
}

.curso-card-titulo {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  line-height: 1.3;
}

.curso-card-subtitulo {
  font-size: 0.85rem;
  color: var(--blanco-muted);
  margin-bottom: 0.75rem;
  font-weight: 300;
}

.curso-card-meta {
  display: flex;
  gap: 1rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--gris);
}

/* ── Cards de desafío ── */
.desafio-card {
  background: var(--obsidiana-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
}

.desafio-card:hover {
  border-color: var(--border-hover);
}

.desafio-video {
  aspect-ratio: 16 / 9;
  background: var(--obsidiana-lighter);
}

.desafio-video iframe {
  width: 100%;
  height: 100%;
  border: none;
}

.desafio-body {
  padding: 2rem;
}

.desafio-titulo {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.desafio-subtitulo {
  color: var(--blanco-muted);
  margin-bottom: 1.5rem;
  font-weight: 300;
}

.desafio-semanas {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.semana {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.semana-header {
  padding: 0.75rem 1rem;
  background: var(--obsidiana-lighter);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background var(--transition);
}

.semana-header:hover {
  background: var(--gris-dark);
}

.semana-titulo {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 500;
}

.semana-subtitulo {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--oro);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.semana-toggle {
  color: var(--oro);
  font-size: 0.8rem;
  transition: transform var(--transition);
}

.semana.open .semana-toggle {
  transform: rotate(180deg);
}

.semana-dias {
  display: none;
  padding: 0;
}

.semana.open .semana-dias {
  display: block;
}

.dia {
  padding: 0.75rem 1rem;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 1rem;
  align-items: baseline;
}

.dia-numero {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--oro);
  min-width: 2.5rem;
  font-weight: 700;
}

.dia-titulo {
  font-weight: 500;
  font-size: 0.9rem;
}

.dia-descripcion {
  font-size: 0.8rem;
  color: var(--blanco-muted);
  font-weight: 300;
  margin-top: 0.15rem;
}

/* ── Página de curso individual ── */
.curso-page {
  padding-top: calc(var(--header-h) + 2rem);
}

.curso-video-main {
  aspect-ratio: 16 / 9;
  background: var(--obsidiana-lighter);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 2rem;
}

.curso-video-main iframe {
  width: 100%;
  height: 100%;
  border: none;
}

.curso-video-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  opacity: 0.2;
}

.curso-layout {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: 2.5rem;
  align-items: start;
}

.curso-breadcrumb {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--gris);
  margin-bottom: 1rem;
}

.curso-breadcrumb a {
  color: var(--gris);
}

.curso-breadcrumb a:hover {
  color: var(--oro);
}

.curso-titulo {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 600;
  margin-bottom: 0.5rem;
  letter-spacing: -0.01em;
}

.curso-subtitulo-page {
  font-size: 1.1rem;
  color: var(--blanco-muted);
  font-weight: 300;
  margin-bottom: 1.5rem;
}

.curso-descripcion {
  color: var(--blanco-soft);
  margin-bottom: 2rem;
  font-weight: 300;
  line-height: 1.8;
}

/* ── Módulos acordeón ── */
.modulos {
  margin-top: 2rem;
}

.modulos-titulo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.modulo {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 0.75rem;
  overflow: hidden;
}

.modulo-header {
  padding: 1rem 1.25rem;
  background: var(--obsidiana-lighter);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background var(--transition);
}

.modulo-header:hover {
  background: var(--gris-dark);
}

.modulo-titulo {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 1rem;
}

.modulo-desc {
  font-size: 0.8rem;
  color: var(--blanco-muted);
  font-weight: 300;
  margin-top: 0.2rem;
}

.modulo-toggle {
  color: var(--oro);
  font-size: 0.8rem;
  transition: transform var(--transition);
  flex-shrink: 0;
}

.modulo.open .modulo-toggle {
  transform: rotate(180deg);
}

.modulo-lecciones {
  display: none;
}

.modulo.open .modulo-lecciones {
  display: block;
}

.leccion {
  padding: 0.75rem 1.25rem;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  transition: background var(--transition);
}

.leccion:hover {
  background: var(--obsidiana-lighter);
}

.leccion.active {
  background: var(--oro-subtle);
  border-left: 2px solid var(--oro);
}

.leccion-titulo {
  font-size: 0.9rem;
  font-weight: 400;
}

.leccion-duracion {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--gris);
}

/* ── Sidebar sticky ── */
.curso-sidebar {
  position: sticky;
  top: calc(var(--header-h) + 2rem);
}

.sidebar-card {
  background: var(--obsidiana-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
}

.sidebar-meta {
  margin-bottom: 1.5rem;
}

.sidebar-meta-item {
  display: flex;
  justify-content: space-between;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}

.sidebar-meta-label {
  color: var(--blanco-muted);
  font-weight: 300;
}

.sidebar-meta-value {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--oro);
}

.sidebar-cta {
  width: 100%;
  margin-bottom: 1.5rem;
}

.sidebar-beneficios {
  list-style: none;
}

.sidebar-beneficios li {
  padding: 0.4rem 0;
  font-size: 0.85rem;
  color: var(--blanco-muted);
  font-weight: 300;
}

.sidebar-beneficios li::before {
  content: '✦ ';
  color: var(--oro);
}

/* ── Filtros catálogo ── */
.filtros {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
  justify-content: center;
}

.filtro-btn {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.6rem 1.25rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: transparent;
  color: var(--blanco-muted);
  cursor: pointer;
  transition: all var(--transition);
}

.filtro-btn:hover {
  border-color: var(--oro);
  color: var(--oro);
}

.filtro-btn.active {
  background: var(--oro);
  color: var(--obsidiana);
  border-color: var(--oro);
}

/* ── CTA Section ── */
.cta-section {
  text-align: center;
  padding: 5rem 1.5rem;
  border-top: 1px solid var(--border);
}

.cta-section h2 {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 600;
  margin-bottom: 1rem;
}

.cta-section p {
  color: var(--blanco-muted);
  margin-bottom: 2rem;
  font-weight: 300;
}

/* ── Footer ── */
.footer {
  margin-top: auto;
  border-top: 1px solid var(--border);
  padding: 2.5rem 1.5rem;
  text-align: center;
}

.footer-ecuacion {
  font-size: 1.25rem;
  letter-spacing: 0.3em;
  margin-bottom: 0.75rem;
}

.footer-marca {
  font-family: var(--font-display);
  font-size: 1rem;
  color: var(--blanco-soft);
  margin-bottom: 0.5rem;
}

.footer-copy {
  font-size: 0.8rem;
  color: var(--gris);
  margin-bottom: 0.75rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  flex-wrap: wrap;
}

.footer-links a {
  font-size: 0.8rem;
  color: var(--gris);
}

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

/* ── Modal ── */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(8px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  padding: 1.5rem;
}

.modal-overlay.active {
  display: flex;
}

.modal {
  background: var(--obsidiana-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  max-width: 480px;
  width: 100%;
  padding: 2.5rem;
  position: relative;
}

.modal-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  color: var(--gris);
  font-size: 1.25rem;
  cursor: pointer;
  transition: color var(--transition);
}

.modal-close:hover {
  color: var(--blanco);
}

.modal h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.modal p {
  color: var(--blanco-muted);
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
  font-weight: 300;
}

.modal-form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.modal-input {
  font-family: var(--font-body);
  font-size: 0.9rem;
  padding: 0.75rem 1rem;
  background: var(--obsidiana);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--blanco);
  outline: none;
  transition: border-color var(--transition);
}

.modal-input:focus {
  border-color: var(--oro);
}

.modal-input::placeholder {
  color: var(--gris);
}

/* ── Cursos relacionados ── */
.relacionados {
  margin-top: 3rem;
  padding-top: 3rem;
  border-top: 1px solid var(--border);
}

.relacionados h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  margin-bottom: 1.5rem;
}

/* ── Animaciones ── */
.fade-in-up {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Responsive ── */
@media (max-width: 1024px) {
  .curso-layout {
    grid-template-columns: 1fr;
  }

  .curso-sidebar {
    position: static;
  }
}

@media (max-width: 768px) {
  .hamburger {
    display: flex;
  }

  .header-nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--obsidiana-light);
    border-left: 1px solid var(--border);
    flex-direction: column;
    justify-content: center;
    padding: 2rem;
    gap: 1.5rem;
    transition: right var(--transition);
  }

  .header-nav.open {
    right: 0;
  }

  .categorias-grid {
    grid-template-columns: 1fr;
  }

  .cursos-grid {
    grid-template-columns: 1fr;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero-stats {
    gap: 1.5rem;
  }

  .section {
    padding: 3rem 0;
  }
}

@media (max-width: 480px) {
  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

  .hero-buttons .btn {
    width: 100%;
    max-width: 280px;
  }

  .filtros {
    gap: 0.5rem;
  }

  .filtro-btn {
    padding: 0.5rem 0.75rem;
    font-size: 0.65rem;
  }
}