*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
img, video, svg { max-width: 100%; height: auto; display: block; }
a { color: var(--color-primary); }
a:hover { color: var(--color-primary-dark); }
:focus-visible { outline: 3px solid var(--color-accent); outline-offset: 3px; border-radius: 4px; }

/* Tipografía: tracking según tamaño (negativo en grande, neutro en cuerpo). */
h1, h2, h3 { margin: 0 0 var(--space-3); color: var(--color-primary-dark); font-weight: 700; }
h1 { font-size: clamp(2.25rem, 5.5vw, 4rem); line-height: 1.04; letter-spacing: -0.025em; }
h2 { font-size: clamp(1.625rem, 3.2vw, 2.5rem); line-height: 1.1; letter-spacing: -0.02em; }
h3 { font-size: 1.125rem; line-height: 1.25; letter-spacing: -0.005em; }
p { margin: 0 0 var(--space-4); }

.container { width: min(100% - 2rem, var(--container)); margin-inline: auto; }
.screen-reader-text {
  position: absolute; width: 1px; height: 1px; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap;
}
.screen-reader-text:focus {
  position: fixed; top: var(--space-3); left: var(--space-3); z-index: 100;
  width: auto; height: auto; clip: auto; padding: var(--space-3) var(--space-4);
  background: var(--color-accent); color: var(--color-primary-dark); font-weight: 700;
}
.site-main { min-height: 50vh; }
.section { padding-block: var(--space-12); }
.section__head { display: flex; align-items: baseline; justify-content: space-between; gap: var(--space-4); margin-bottom: var(--space-6); }
.section__head a { font-weight: 600; text-decoration: none; }

/* Botones: respuesta inmediata al presionar. */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: var(--space-2);
  min-height: 3rem; padding: 0 var(--space-6);
  border: 0; border-radius: 999px; cursor: pointer;
  font: 700 1rem/1 var(--font-sans); text-decoration: none;
  transition: transform var(--dur-fast) var(--ease-spring), box-shadow var(--dur-fast) var(--ease-spring), background-color var(--dur-fast);
}
.btn:active { transform: scale(0.97); transition-duration: var(--dur-press); }
.btn--accent { background: var(--color-accent); color: var(--color-primary-dark); }
.btn--accent:hover { color: var(--color-primary-dark); box-shadow: var(--shadow-2); transform: translateY(-1px); }
.btn--ghost { background: rgb(255 255 255 / 0.14); color: #fff; }
.btn--ghost:hover { color: #fff; background: rgb(255 255 255 / 0.24); }

/* Revelado al hacer scroll: solo transform y opacity. */
[data-reveal] { opacity: 0; transform: translateY(16px); }
[data-reveal].is-in {
  opacity: 1; transform: none;
  transition: opacity var(--dur) var(--ease-spring), transform var(--dur) var(--ease-spring);
  transition-delay: calc(var(--i, 0) * 50ms);
}
.no-js [data-reveal] { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  [data-reveal] { transform: none; }
  [data-reveal].is-in { transition: opacity var(--dur) linear; transition-delay: 0ms; }
  .btn:active { transform: none; }
}
.section__sub { margin: var(--space-2) 0 0; color: #3d5566; font-size: 1.0625rem; max-width: 40rem; }