/* ===========================================================================
   base.css — reset mínimo, tipografía base, layout, accesibilidad y utilidades
   PLAN.md §4 (comportamiento), §6.2 (tipografía), §4.7 (accesibilidad)
   =========================================================================== */

/* ---------------------------------------------------------------------------
   Reset mínimo
   --------------------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

* {
  margin: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  font-weight: var(--fw-regular);
  line-height: var(--lh-text);
  color: var(--text);
  background-color: var(--bg);
  text-rendering: optimizeLegibility;
}

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

input,
button,
select,
textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
}

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

a:hover {
  text-decoration: underline;
}

ul[role="list"],
ol[role="list"] {
  list-style: none;
  padding: 0;
}

/* ---------------------------------------------------------------------------
   Tipografía base (§6.2)
   --------------------------------------------------------------------------- */
h1,
h2,
h3,
h4 {
  line-height: var(--lh-title);
  font-weight: var(--fw-bold);
  letter-spacing: var(--tracking-tight);
  text-wrap: balance;
}

h1 {
  font-size: var(--fs-hero);
  font-weight: var(--fw-black);
  line-height: var(--lh-hero);
}

h2 {
  font-size: var(--fs-3xl);
}

h3 {
  font-size: var(--fs-2xl);
  font-weight: var(--fw-semibold);
}

h4 {
  font-size: var(--fs-xl);
  font-weight: var(--fw-semibold);
  letter-spacing: 0;
}

p {
  max-width: var(--measure);
}

strong {
  font-weight: var(--fw-semibold);
}

small {
  font-size: var(--fs-sm);
}

/* ---------------------------------------------------------------------------
   Layout: contenedor y secciones (§4.1)
   --------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

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

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

/* Compensar el header sticky al saltar a anclas (§4.6) */
[id] {
  scroll-margin-top: calc(var(--header-h) + var(--space-4));
}

/* ---------------------------------------------------------------------------
   Accesibilidad (§4.7)
   --------------------------------------------------------------------------- */

/* Enlace "Saltar al contenido" — visible solo al enfocar */
.skip-link {
  position: fixed;
  top: var(--space-2);
  left: var(--space-2);
  z-index: 1000;
  padding: var(--space-2) var(--space-4);
  background: var(--btn-bg);
  color: var(--btn-text);
  border-radius: var(--radius-md);
  font-weight: var(--fw-medium);
  transform: translateY(-150%);
  transition: transform 0.15s ease-in;
}

.skip-link:focus {
  transform: translateY(0);
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  text-decoration: none;
}

/* Anillo de foco visible solo con navegación por teclado */
:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Ocultar visualmente pero accesible a lectores de pantalla */
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ---------------------------------------------------------------------------
   Breakpoints (§4.1): gutter 24 a ≥768, 32 a ≥1024; sección 96 a ≥1024
   --------------------------------------------------------------------------- */
@media (min-width: 768px) {
  :root {
    --gutter: 24px;
  }
}

@media (min-width: 1024px) {
  :root {
    --gutter: 32px;
    --section-py: 96px;
  }
}

/* ---------------------------------------------------------------------------
   Movimiento (§4.6)
   --------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}