.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header--landing {
  position: absolute;
  inset: 0 0 auto;
  border-bottom: 0;
  background: transparent;
  z-index: 20;
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
  padding: var(--space-md) 0;
}

.site-header--landing .site-header__inner {
  padding: var(--landing-header-top-pad) 0 0;
  align-items: flex-start;
}

.site-header--landing .site-nav {
  margin-top: var(--landing-nav-offset);
}

.site-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
}

.site-brand img {
  display: block;
  width: auto;
  height: var(--header-logo-height);
}

.site-header--landing .site-brand img {
  height: var(--header-logo-height-landing);
}

.site-nav > ul {
  display: flex;
  align-items: center;
  gap: var(--space-text-md);
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-header--landing .site-nav > ul {
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: var(--landing-nav-gap-compact);
  max-width: 42rem;
}

.site-nav__item {
  position: relative;
}

.site-nav__item--has-children {
  padding-bottom: var(--space-text-md);
  margin-bottom: calc(var(--space-text-md) * -1);
}

.site-nav__submenu {
  position: absolute;
  top: calc(100% + var(--nav-flyout-offset));
  left: 50%;
  z-index: 30;
  display: grid;
  gap: var(--space-panel-sm);
  min-width: var(--nav-flyout-min-width);
  margin: 0;
  padding: var(--space-panel-md);
  border: 1px solid var(--color-nav-submenu-border);
  border-radius: var(--nav-flyout-radius);
  background: var(--color-nav-submenu-bg);
  box-shadow: 0 18px 40px var(--color-nav-submenu-shadow);
  list-style: none;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateX(-50%) translateY(-0.35rem);
  transition:
    opacity 160ms ease,
    transform 160ms ease,
    visibility 160ms ease;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.site-nav__submenu::before {
  content: "";
  position: absolute;
  inset: calc(var(--space-text-md) * -1) 0 auto;
  height: 0.9rem;
}

.site-nav a,
.site-nav__submenu a,
.text-link,
.link-list a {
  text-decoration: none;
}

.site-nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: var(--nav-touch-target);
  padding: var(--space-panel-sm) var(--space-text-md);
  border-radius: 999px;
  font-size: 1rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.site-nav__submenu a {
  display: flex;
  justify-content: center;
  width: 100%;
  min-height: 0;
  padding: var(--space-text-xs) 0.6rem;
  border-radius: 999px;
  white-space: nowrap;
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-align: center;
}

.site-nav__submenu a:hover,
.site-nav__submenu a:focus-visible {
  background: var(--color-surface-muted);
  outline: none;
}

.site-nav__item--has-children:hover > .site-nav__submenu,
.site-nav__item--has-children:focus-within > .site-nav__submenu {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

.site-nav a[aria-current="page"] {
  color: var(--color-accent);
  font-weight: 700;
}

.site-nav a[aria-disabled="true"] {
  color: var(--color-nav-disabled);
  cursor: default;
  pointer-events: none;
}

.site-header--landing .site-nav a {
  min-height: var(--nav-touch-target-landing);
  padding: 0.25rem 0.6rem;
  color: var(--color-text-soft);
  background: var(--color-accent);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  box-shadow: inset 0 0 0 1px var(--color-landing-nav-inset);
}

.site-header--landing .site-nav__submenu a {
  color: var(--color-text-soft);
  background: var(--color-accent);
  box-shadow: none;
}

.site-header--landing .site-nav a[aria-current="page"],
.site-header--landing .site-nav a:hover,
.site-header--landing .site-nav a:focus-visible,
.site-header--landing .site-nav__submenu a:hover,
.site-header--landing .site-nav__submenu a:focus-visible {
  color: var(--color-accent);
  background: var(--color-surface);
  outline: none;
}

.site-header--landing .site-nav__submenu a[aria-current="page"] {
  color: var(--color-surface);
  background: var(--color-accent-soft);
}

.site-header--landing .site-nav a[aria-disabled="true"] {
  color: var(--color-landing-nav-disabled);
  background: var(--color-landing-nav-disabled-bg);
  box-shadow: none;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-panel-md);
  border: 1px solid var(--color-nav-toggle-border);
  border-radius: 999px;
  background: var(--color-nav-toggle-bg);
  padding: var(--space-panel-md) var(--space-sm);
  font: inherit;
  color: var(--color-text-soft);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.site-header--landing .nav-toggle:hover,
.site-header--landing .nav-toggle:focus-visible {
  background: var(--color-nav-toggle-hover);
  outline: none;
}

.nav-toggle__box {
  display: inline-grid;
  gap: var(--space-2xs);
}

.nav-toggle__line {
  display: block;
  width: 1rem;
  height: 2px;
  border-radius: 999px;
  background: currentColor;
  transform-origin: center;
  transition: transform 180ms ease, opacity 180ms ease;
}

.nav-toggle__label {
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(1) {
  transform: translateY(0.4rem) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(3) {
  transform: translateY(-0.4rem) rotate(-45deg);
}

@media (max-width: 700px) {
  .site-header--landing .site-nav {
    margin-top: var(--landing-nav-offset-md);
  }
}

@media (max-width: 520px) {
  .site-header__inner {
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: start;
  }

  .nav-toggle {
    display: inline-flex;
    justify-self: end;
  }

  .site-nav {
    display: none;
    width: 100%;
  }

  .site-nav.is-open {
    display: block;
  }

  .site-nav > ul {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
    
    padding-top: var(--space-sm);
  }

  .site-nav__item {
    width: 100%;
  }

  .site-nav__submenu {
    position: static;
    display: grid;
    min-width: 0;
    margin-top: var(--space-xs);
    margin-left: var(--space-sm);
    padding: var(--space-xs) 0 0 var(--space-md);
    border: 0;
    border-left: 1px solid var(--color-nav-mobile-divider);
    border-radius: 0;
    background: transparent;
    box-shadow: none;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: none;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
  }

  .site-nav__submenu::before {
    content: none;
  }

  .site-nav__submenu a {
    padding: var(--space-2xs) 0;
    border-radius: 0;
    font-size: 0.95rem;
  }

  .site-nav__submenu a:hover,
  .site-nav__submenu a:focus-visible {
    background: transparent;
  }

  .site-nav__item--has-children:hover > .site-nav__submenu,
  .site-nav__item--has-children:focus-within > .site-nav__submenu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: none;
  }

  .site-header--landing .site-header__inner {
    padding-top: var(--landing-header-top-pad-sm);
  }

  .site-header--landing .site-brand img {
    height: var(--header-logo-height-landing-sm);
  }

  .site-header--landing .site-nav {
    grid-column: 1 / -1;
    margin-top: var(--landing-nav-offset-sm);
    padding: var(--space-sm);
    border: 1px solid var(--color-landing-mobile-nav-border);
    border-radius: var(--landing-mobile-panel-radius);
    background: var(--color-landing-mobile-nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
  }

  .site-header--landing .site-nav > ul {
    justify-content: flex-start;
    max-width: none;
  }

  .site-header--landing .site-nav a {
    width: 100%;
    justify-content: flex-start;
    min-height: var(--nav-touch-target-mobile);
    padding: var(--space-xs) var(--space-panel-lg);
    border-radius: var(--space-panel-lg);
  }
}