html {
  background: var(--color-bg);
}

body {
  font-family: var(--font-family-base);
  background: var(--color-bg);
  color: var(--color-text);
  font-size: var(--fs-base);
  overflow-x: hidden;
}

/* Fondo tecnológico sutil, fijo, no interactivo */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -2;
  background:
    radial-gradient(60rem 40rem at 12% -10%, rgba(79, 107, 255, 0.16), transparent 60%),
    radial-gradient(50rem 36rem at 100% 10%, rgba(0, 212, 255, 0.10), transparent 55%),
    radial-gradient(60rem 50rem at 50% 120%, rgba(139, 92, 246, 0.12), transparent 60%),
    var(--color-bg);
  pointer-events: none;
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(rgba(148, 163, 184, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.05) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 40%, transparent 90%);
  pointer-events: none;
}

/* Enlace de salto para accesibilidad por teclado */
.skip-link {
  position: absolute;
  left: 1rem;
  top: -60px;
  z-index: 200;
  background: var(--color-primary);
  color: #fff;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  transition: top var(--transition-base);
}

.skip-link:focus {
  top: 1rem;
}

/* Foco visible consistente */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--color-cyan);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* Layout */
.section-shell {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

.section {
  padding-block: var(--space-12);
}

.section-kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  font-size: var(--fs-xs);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-cyan);
  margin-bottom: var(--space-3);
}

/* Indicador de "sistema activo": punto luminoso con pulso sutil. */
.section-kicker::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-cyan);
  box-shadow: 0 0 8px rgba(0, 212, 255, 0.8);
  flex-shrink: 0;
  animation: kicker-pulse 2.4s ease-in-out infinite;
}

@keyframes kicker-pulse {
  0%, 100% { opacity: 0.5; transform: scale(0.85); }
  50% { opacity: 1; transform: scale(1.15); }
}

.section-header {
  max-width: 44rem;
  margin-bottom: var(--space-8);
}

.section-header h2 {
  font-size: clamp(var(--fs-2xl), 4vw, var(--fs-4xl));
  margin-bottom: var(--space-4);
}

.section-header p {
  color: var(--color-muted);
  font-size: var(--fs-lg);
}

.text-gradient {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

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

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

.hidden {
  display: none !important;
}

/* Animación de entrada suave.
   El estado oculto SOLO aplica cuando JS confirma que animará (html.js-anim):
   sin JavaScript, con reduced-motion o si el observer falla, todo el
   contenido es visible desde el primer render. */
html.js-anim .fade-up {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

html.js-anim .fade-up.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html.js-anim .fade-up {
    opacity: 1;
    transform: none;
    transition: none;
  }
}