@property --bar-h {
  syntax: "<length>";
  inherits: true;
  initial-value: 88px;
}

/* ==========================================================================
   Header — fixed navigation, scroll behaviour, mobile menu
   ========================================================================== */

.site-header {
  --bar-h: var(--header-h);
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  transition:
    transform 0.6s var(--ease-out),
    --bar-h 0.5s var(--ease-out);
}

.site-header.is-compact {
  --bar-h: var(--header-h-compact);
}

/* Header slides away while reading downwards, returns on the first upward scroll */
.site-header.is-hidden {
  transform: translateY(-101%);
}

/* Frosted anthracite plate, only once content scrolls beneath the bar */
.site-header::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: var(--bar-h);
  background: rgb(16 17 18 / 0.86);
  -webkit-backdrop-filter: blur(14px) saturate(1.2);
  backdrop-filter: blur(14px) saturate(1.2);
  border-bottom: 1px solid var(--c-line);
  opacity: 0;
  transition: opacity 0.5s var(--ease-out);
  pointer-events: none;
}

.site-header.is-compact::before,
.site-header.is-menu-open::before {
  opacity: 1;
}

.site-header__bar {
  position: relative;
  z-index: 2;
  max-width: var(--container-max);
  margin-inline: auto;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  height: var(--bar-h);
  padding-inline: var(--gutter);
  transition: height 0.5s var(--ease-out);
}

/* Brand ------------------------------------------------------------------ */
.brand {
  justify-self: start;
  display: inline-flex;
  align-items: center;
  height: 100%;
}

.brand__logo {
  height: 3.1rem;
  width: auto;
  transition: height 0.5s var(--ease-out);
}

.site-header.is-compact .brand__logo {
  height: 2.5rem;
}

/* Primary nav ------------------------------------------------------------- */
.primary-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(1.75rem, 3.4vw, 3.5rem);
}

.nav-link {
  position: relative;
  display: inline-block;
  padding-block: 0.5rem;
  font-size: 0.9375rem;
  letter-spacing: 0.015em;
  color: var(--c-paper-nav);
  transition: color var(--dur-base) var(--ease-out);
}

.nav-link::after {
  content: "";
  position: absolute;
  inset: auto 0 0.2rem 0;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.6s var(--ease-out);
}

a.nav-link[href]:hover,
a.nav-link[href]:focus-visible,
.nav-link[aria-current="true"] {
  color: var(--c-paper);
}

a.nav-link[href]:hover::after,
a.nav-link[href]:focus-visible::after,
.nav-link[aria-current="true"]::after {
  transform: scaleX(1);
  transform-origin: left;
}

/* CTA --------------------------------------------------------------------- */
.site-header__cta {
  justify-self: end;
  padding: 0.8rem 1.35rem;
  font-size: 0.875rem;
}

/* Menu toggle (mobile) ---------------------------------------------------- */
.menu-toggle {
  display: none;
  position: relative;
  justify-self: end;
  width: 2.75rem;
  height: 2.75rem;
  margin-right: -0.65rem;
}

.menu-toggle__bar {
  position: absolute;
  left: 0.7rem;
  right: 0.7rem;
  height: 1px;
  background: var(--c-paper);
  transition:
    transform 0.6s var(--ease-out),
    top 0.6s var(--ease-out);
}

.menu-toggle__bar:nth-child(1) {
  top: calc(50% - 4px);
}

.menu-toggle__bar:nth-child(2) {
  top: calc(50% + 4px);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__bar:nth-child(1) {
  top: 50%;
  transform: rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__bar:nth-child(2) {
  top: 50%;
  transform: rotate(-45deg);
}

/* Mobile menu ------------------------------------------------------------- */
.mobile-menu {
  display: none;
}

@media (max-width: 959.98px) {
  .primary-nav,
  .site-header__cta {
    display: none;
  }

  .site-header__bar {
    grid-template-columns: 1fr auto;
  }

  .brand__logo {
    height: 2.75rem;
  }

  .site-header.is-compact .brand__logo {
    height: 2.4rem;
  }

  .menu-toggle {
    display: block;
  }

  .mobile-menu {
    position: fixed;
    inset: 0;
    z-index: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 2rem;
    padding: calc(var(--header-h) + 1.5rem) var(--gutter) max(1.75rem, env(safe-area-inset-bottom));
    background: var(--c-ink-900);
    overflow-y: auto;
    visibility: hidden;
    clip-path: inset(0 0 100% 0);
    transition:
      clip-path 0.8s var(--ease-in-out),
      visibility 0s linear 0.8s;
  }

  .site-header.is-menu-open .mobile-menu {
    visibility: visible;
    clip-path: inset(0 0 0 0);
    transition:
      clip-path 0.8s var(--ease-in-out),
      visibility 0s;
  }

  .mobile-menu__list {
    display: flex;
    flex-direction: column;
  }

  .mobile-menu__item {
    border-top: 1px solid var(--c-line);
  }

  .mobile-menu__item:last-child {
    border-bottom: 1px solid var(--c-line);
  }

  .mobile-menu__link {
    display: flex;
    align-items: baseline;
    gap: 1.1rem;
    padding-block: 0.95rem;
    font-family: var(--f-serif);
    font-size: clamp(2.35rem, 11vw, 3.25rem);
    line-height: 1.05;
    letter-spacing: -0.01em;
    color: var(--c-paper);
  }

  .mobile-menu__num {
    min-width: 1.6rem;
    font-family: var(--f-sans);
    font-size: 0.75rem;
    letter-spacing: 0.08em;
    color: var(--c-oak);
  }

  .mobile-menu__foot {
    display: grid;
    gap: 1.5rem;
  }

  .mobile-menu__foot .btn {
    justify-content: space-between;
    width: 100%;
    padding-block: 1.1rem;
  }

  .mobile-menu__contact {
    display: grid;
    gap: 0.35rem;
    font-size: 0.9375rem;
    color: var(--c-paper-dim);
  }

  .mobile-menu__contact a {
    width: fit-content;
    padding-block: 0.5rem; /* 44 px tap target */
    color: var(--c-paper);
    text-decoration: underline;
    text-decoration-color: var(--c-line-strong);
    text-underline-offset: 0.3em;
  }

  /* staggered entrance of the menu content */
  .mobile-menu__item,
  .mobile-menu__foot {
    opacity: 0;
    transform: translateY(1.25rem);
    transition:
      opacity 0.5s var(--ease-out),
      transform 0.8s var(--ease-out);
  }

  .site-header.is-menu-open .mobile-menu__item,
  .site-header.is-menu-open .mobile-menu__foot {
    opacity: 1;
    transform: none;
    transition-delay: calc(0.28s + var(--i, 0) * 70ms);
  }
}

/* Entrance on first load -------------------------------------------------- */
.js:not(.is-loaded) .site-header__bar > * {
  opacity: 0;
}

.js.is-loaded .site-header__bar > * {
  animation: header-in 1.1s var(--ease-out) backwards;
}

.js.is-loaded .site-header__bar > :nth-child(2) {
  animation-delay: 0.1s;
}

.js.is-loaded .site-header__bar > :nth-child(3) {
  animation-delay: 0.2s;
}

@keyframes header-in {
  from {
    opacity: 0;
    transform: translateY(-0.6rem);
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-header,
  .site-header::before,
  .site-header__bar,
  .brand__logo,
  .menu-toggle__bar,
  .mobile-menu,
  .mobile-menu__item,
  .mobile-menu__foot,
  .nav-link::after {
    transition-duration: 0.01ms !important;
    transition-delay: 0s !important;
  }

  .js.is-loaded .site-header__bar > * {
    animation: none;
  }
}