/* ============================================================
   HEADER — Skip link · Site header · Nav · Lang switch ·
             Theme toggle · Mobile nav toggle
   ============================================================ */

/* ---- SKIP LINK ---- */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--sp-4);
  z-index: 200;
  padding: var(--sp-3) var(--sp-5);
  background: var(--accent);
  color: #fff;
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--r-sm);
  transition: top var(--dur-fast);
}
.skip-link:focus {
  top: var(--sp-4);
}

/* ---- SITE HEADER ---- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: 64px;
  display: flex;
  align-items: center;
  background-color: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(16px) saturate(140%);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  border-bottom: 1px solid var(--border-subtle);
  transition:
    background-color var(--dur-mid) var(--ease-out),
    border-color var(--dur-mid);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: 100%;
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 5vw, 3rem);
}
.site-header__logo {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 500;
  color: var(--ink);
  letter-spacing: -0.01em;
  transition: color var(--dur-fast);
  display: flex;
  align-items: center;
}
.site-header__logo img,
.site-header__logo-svg {
  display: block;
  height: 22px;
  width: auto;
}
.site-header__logo-svg path {
  fill: var(--ink);
  transition: fill var(--dur-mid) var(--ease-out);
}
.site-header__logo:hover .site-header__logo-svg path {
  fill: var(--accent);
}
.site-header__logo:hover {
  color: var(--accent);
}
.site-header__nav {
  display: flex;
  align-items: center;
  gap: var(--sp-8);
}
.site-header__nav-link {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-1);
  font-size: var(--text-sm);
  font-weight: 400;
  color: var(--ink-3);
  letter-spacing: 0.02em;
  transition: color var(--dur-fast);
  position: relative;
}
button.site-header__nav-link {
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  font-family: var(--font-body);
}
.site-header__nav-link::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--accent);
  transition: width var(--dur-mid) var(--ease-out);
}
.site-header__nav-link:hover {
  color: var(--ink);
}
.site-header__nav-link:hover::after,
.site-header__nav-link--active::after {
  width: 100%;
}
.site-header__nav-link--active {
  color: var(--ink);
}
.site-header__controls {
  display: flex;
  align-items: center;
  gap: var(--sp-4);
}
/* Wrapper único: apila nav y compact en la misma celda del grid */
.site-header__center {
  display: grid;
  place-items: center;
}
.site-header__center .site-header__nav,
.site-header__center .site-header__case-compact {
  grid-area: 1 / 1;
}
/* Estado inicial: nav visible, compact oculto */
.site-header__center .site-header__nav {
  transition:
    opacity var(--dur-fast) var(--ease-out),
    transform var(--dur-fast) var(--ease-out),
    visibility var(--dur-fast);
  transition-delay: 160ms;
}
.site-header__case-compact {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: var(--sp-4);
  font-size: var(--text-sm);
  font-family: var(--font-mono);
  color: var(--ink-2);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition:
    opacity 160ms var(--ease-out),
    transform 160ms var(--ease-out),
    visibility 160ms;
  pointer-events: none;
}
.site-header__case-compact #qs-compact-role {
  color: var(--ink);
  font-weight: 500;
}
/* Al scrollear: nav sale primero, compact entra después */
.site-header--case-scrolled .site-header__center .site-header__nav {
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  pointer-events: none;
  transition-delay: 0ms;
}
.site-header--case-scrolled .site-header__case-compact {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  pointer-events: auto;
  transition-delay: 160ms;
}

/* ---- LANG SWITCH ---- */
.lang-switch {
  display: flex;
  align-items: center;
  gap: 2px;
  padding: var(--sp-1) var(--sp-2);
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  background: transparent;
  transition: border-color var(--dur-fast);
}
.lang-switch:hover {
  border-color: var(--ink-3);
}
.lang-switch__btn {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-3); /* a11y: es texto interactivo, --ink-4 no pasa AA */
  padding: 2px var(--sp-2);
  border-radius: 2px;
  transition:
    color var(--dur-fast),
    background var(--dur-fast);
}
.lang-switch__btn--active {
  color: var(--ink);
  background: var(--surface);
}
.lang-switch__btn:hover:not(.lang-switch__btn--active) {
  color: var(--ink-2);
}

/* ---- THEME TOGGLE ---- */
.theme-toggle {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--r-sm);
  color: var(--ink-3);
  transition:
    color var(--dur-fast),
    background var(--dur-fast);
}
.theme-toggle:hover {
  color: var(--ink);
  background: var(--surface);
}
.theme-toggle:focus-visible {
  outline: 2px solid var(--accent-ink);
  outline-offset: 2px;
  background: var(--surface);
}
.theme-toggle svg {
  width: 18px;
  height: 18px;
}
.icon-sun {
  display: none;
}
.icon-moon {
  display: block;
}
html.theme-dark .icon-sun {
  display: block;
}
html.theme-dark .icon-moon {
  display: none;
}

/* ---- MOBILE NAV TOGGLE ---- */
.nav-toggle:focus-visible {
  outline: 2px solid var(--accent-ink);
  outline-offset: 2px;
}
.nav-toggle {
  display: none;
  width: 36px;
  height: 36px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--ink-3);
  transition:
    transform var(--dur-mid) var(--ease-out),
    opacity var(--dur-mid);
}
@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }
  .site-header__nav {
    display: none;
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: var(--sp-6);
    gap: var(--sp-5);
  }
  .site-header__nav.is-open {
    display: flex;
  }
}