/* Cabecera fija: transparente (blanca) sobre el hero, sólida al bajar; se esconde al bajar y vuelve al subir. */
.site-header {
  position: fixed; inset: 0 0 auto; z-index: 60; height: var(--header-h);
  display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: var(--s3);
  padding: 0 var(--gutter); color: var(--ink);
  transition: transform var(--t-mid) var(--ease-cut), background-color var(--t-fast) linear, color var(--t-fast) linear;
}
.site-header::after { content: ""; position: absolute; left: var(--gutter); right: var(--gutter); bottom: 0; height: 1px;
  background: currentColor; opacity: 0; transform: scaleX(0); transform-origin: 0 0;
  transition: transform var(--t-slow) var(--ease-grow), opacity var(--t-fast); }
.site-header[data-theme="dark"]:not(.is-solid) { color: #fff; }
.site-header.is-solid { background: rgb(255 255 255 / 0.94); -webkit-backdrop-filter: blur(10px); backdrop-filter: blur(10px); }
.site-header.is-solid::after { opacity: 0.12; transform: scaleX(1); }
.site-header.is-hidden { transform: translateY(-101%); }
html.menu-open .site-header.site-header[data-theme] { color: var(--ink); background: transparent; transform: none; -webkit-backdrop-filter: none; backdrop-filter: none; }
html.menu-open .site-header::after { opacity: 0; }

.brand { display: block; width: clamp(150px, 13vw, 196px); color: inherit; }
.brand__logo { width: 100%; height: auto; }

.nav { justify-self: center; }
.nav__list { display: flex; gap: clamp(1.2rem, 2.4vw, 2.6rem); }
.nav__link { position: relative; text-decoration: none; font-weight: 400; font-size: 0.95rem; padding: 0.4em 0; }
.nav__link::after { content: ""; position: absolute; left: 0; bottom: 0; width: 100%; height: 1px; background: currentColor;
  transform: scaleX(0); transform-origin: 100% 0; transition: transform var(--t-mid) var(--ease-cut); }
.nav__link:hover::after, .nav__link[aria-current="page"]::after { transform: scaleX(0.618); transform-origin: 0 0; }

.site-header__tools { display: flex; align-items: center; gap: var(--s2); }
.lang { display: flex; gap: 0.15rem; font: 400 0.74rem/1 var(--mono); letter-spacing: 0.08em; }
.lang__item { padding: 0.55em 0.45em; text-decoration: none; opacity: 0.55; }
.lang__item.is-current { opacity: 1; border-bottom: 1px solid currentColor; }
.lang__item:hover { opacity: 1; }
.pill { display: inline-flex; align-items: center; gap: 0.62em; padding: 0.78em 1.2em; border: 1px solid currentColor;
  font: 400 0.76rem/1 var(--mono); letter-spacing: 0.1em; text-transform: uppercase; text-decoration: none;
  transition: background-color var(--t-fast), color var(--t-fast), border-color var(--t-fast); }
.pill__dot { width: 0.5em; height: 0.5em; background: var(--olive); border-radius: 50%; }
.site-header[data-theme="dark"]:not(.is-solid) .pill__dot { background: var(--olive-light); }
.pill:hover { background: var(--ink); color: #fff; border-color: var(--ink); }

.burger { display: none; width: 44px; height: 44px; place-items: center; }
.burger__box { position: relative; width: 26px; height: 16px; }
.burger__box i { position: absolute; left: 0; height: 1.5px; background: currentColor;
  transition: transform var(--t-mid) var(--ease-cut), width var(--t-mid) var(--ease-cut), top var(--t-mid) var(--ease-cut); }
.burger__box i:first-child { top: 3px; width: 100%; }
.burger__box i:last-child { top: 12px; width: 61.8%; }
.burger[aria-expanded="true"] .burger__box i:first-child { top: 7.5px; transform: rotate(45deg); }
.burger[aria-expanded="true"] .burger__box i:last-child { top: 7.5px; width: 100%; transform: rotate(-45deg); }

/* ---- Menú móvil: dos paneles en proporción áurea (61,8 % baja, 38,2 % sube) ---------------------- */
.menu { position: fixed; inset: 0; z-index: 55; visibility: hidden; pointer-events: none; }
.menu[hidden] { display: none; }
.menu__panel { position: absolute; top: 0; bottom: 0; background: var(--paper); transform: translateY(-101%);
  transition: transform 0.7s var(--ease-cut); }
.menu__panel--a { left: 0; width: 61.8%; }
.menu__panel--b { right: 0; width: 38.2%; background: var(--olive-soft); transform: translateY(101%); transition-delay: 0.08s; }
.menu__inner { position: relative; height: 100%; overflow-y: auto; padding: calc(var(--header-h) + var(--s3)) var(--gutter) var(--s3);
  display: flex; flex-direction: column; justify-content: space-between; gap: var(--s3); opacity: 0;
  transition: opacity 0.3s linear; }
.menu__list { display: grid; gap: 0.15rem; }
.menu__link { display: flex; align-items: baseline; gap: 1rem; padding: 0.3rem 0; text-decoration: none;
  font: 400 clamp(2.4rem, 11vw, 4rem)/1.04 var(--serif); letter-spacing: -0.02em; }
.menu__link-n { font: 400 0.7rem/1 var(--mono); color: var(--olive); letter-spacing: 0.06em; min-width: 3.2em; }
.menu__link[aria-current="page"] .menu__link-t { font-style: italic; }
.menu__meta { display: grid; gap: 0.5rem; font-size: 0.95rem; }
.menu__meta a { text-decoration: none; }
.menu-lang { display: flex; gap: 0.8rem; margin-top: 0.6rem; font: 400 0.8rem/1 var(--mono); letter-spacing: 0.1em; }
.menu-lang__item { padding: 0.6em 0; text-decoration: none; opacity: 0.55; }
.menu-lang__item.is-current { opacity: 1; border-bottom: 1px solid currentColor; }
html.menu-open .menu { visibility: visible; pointer-events: auto; }
html.menu-open .menu__panel { transform: none; }
html.menu-open .menu__inner { opacity: 1; transition-delay: 0.35s; }
html.menu-open body { overflow: hidden; }

@media (max-width: 1099px) {
  .nav, .site-header__tools > .lang { display: none; }
  .burger { display: grid; }
  .site-header { grid-template-columns: auto 1fr auto; }
  .site-header__tools { grid-column: 3; }
}
@media (max-width: 520px) {
  .pill { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  .menu__panel, .menu__inner, .site-header { transition: none; }
}