/* Header layout */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-xs);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-3);
  padding-bottom: var(--space-3);
  gap: var(--space-4);
}

/* Brand */
.site-header__brand {
  display: flex;
  align-items: center;
}

.site-header__logo-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
}

.site-header__logo-mark {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 999px;
  background-color: var(--color-primary-soft);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary-strong);
  box-shadow: var(--shadow-sm);
  flex-shrink: 0;
}

.site-header__logo-mark i {
  font-size: 1.2rem;
}

.site-header__text {
  display: flex;
  flex-direction: column;
}

.site-header__site-name {
  font-weight: 700;
  font-size: var(--font-size-lg);
  color: var(--color-text);
}

.site-header__tagline {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

/* Navigation */
.site-header__nav {
  margin-left: auto;
}

.site-header__nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  list-style: none;
  padding: 0;
  margin: 0;
}

.site-header__nav-link {
  position: relative;
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 0.25rem 0;
}

.site-header__nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -0.2rem;
  width: 0;
  height: 2px;
  background-color: var(--color-primary);
  transition: width var(--transition-normal);
}

.site-header__nav-link:hover,
.site-header__nav-link:focus-visible {
  color: var(--color-primary-strong);
}

.site-header__nav-link:hover::after,
.site-header__nav-link:focus-visible::after {
  width: 100%;
}

.site-header__nav-item--secondary .site-header__nav-link--accent {
  padding: 0.35rem 0.9rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-primary);
  background-color: var(--color-primary-soft);
  color: var(--color-primary-strong);
}

.site-header__nav-item--secondary .site-header__nav-link--accent::after {
  display: none;
}

.site-header__nav-item--secondary .site-header__nav-link--accent:hover,
.site-header__nav-item--secondary .site-header__nav-link--accent:focus-visible {
  background-color: var(--color-primary);
  color: #ffffff;
}

/* Mobile toggle */
.site-header__toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 0.2rem;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 999px;
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text);
  cursor: pointer;
}

.site-header__toggle-bar {
  width: 1.3rem;
  height: 2px;
  border-radius: 999px;
  background-color: var(--color-text);
  transition: transform var(--transition-normal), opacity var(--transition-normal);
}

/* Hide toggle on larger screens */
@media (min-width: 960px) {
  .site-header__toggle {
    display: none;
  }
}

/* Mobile nav behaviour: nav visible by default (no JS), but stacked; JS enhances to collapse. */
@media (max-width: 959.98px) {
  .site-header__inner {
    flex-wrap: wrap;
    align-items: flex-start;
  }

  .site-header__nav {
    width: 100%;
    order: 3;
  }

  .site-header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    padding-bottom: var(--space-3);
  }

  .site-header__nav-link {
    display: block;
    width: 100%;
    padding: 0.4rem 0;
  }

  .site-header--js-enabled .site-header__nav {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow) ease;
  }

  .site-header--js-enabled .site-header__nav--open {
    max-height: 26rem;
  }

  .site-header--menu-open .site-header__toggle-bar:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }

  .site-header--menu-open .site-header__toggle-bar:nth-child(2) {
    opacity: 0;
  }

  .site-header--menu-open .site-header__toggle-bar:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }
}

/* Utility: visually hidden but still readable when necessary (for JS enhancements) */
.site-header__nav--hidden-nojs {
  /* left intentionally empty; JS will toggle classes that rely on transitions above */
}