/* Header layout */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: var(--color-surface);
  box-shadow: var(--shadow-sm);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-10);
  padding-bottom: var(--space-10);
  gap: var(--space-16);
}

/* Branding */
.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-8);
  text-decoration: none;
}

.site-header__logo-mark {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-primary) 0%, #0a5a92 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: var(--shadow-sm);
}

.site-header__logo-icon {
  font-size: 1.1rem;
}

.site-header__brand-text {
  display: flex;
  flex-direction: column;
}

.site-header__brand-name {
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-size: var(--font-size-sm);
}

.site-header__brand-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-12);
}

.site-header__nav-link {
  position: relative;
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--gray-700);
  padding: 0.25rem 0;
}

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

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

.site-header__nav-item--cta {
  margin-left: var(--space-8);
}

.site-header__cta {
  font-size: var(--font-size-sm);
  padding-inline: 1.3rem;
}

/* Mobile toggle */
.site-header__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  border: 1px solid var(--gray-200);
  background-color: #ffffff;
  cursor: pointer;
}

.site-header__toggle-bar {
  width: 18px;
  height: 2px;
  border-radius: 999px;
  background-color: var(--gray-700);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.site-header__toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
}

/* Toggle animation */
.site-header__toggle--open .site-header__toggle-bar:nth-child(1) {
  transform: translateY(4px) rotate(45deg);
}

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

.site-header__toggle--open .site-header__toggle-bar:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* Mobile navigation behaviour */
@media (max-width: 768px) {
  .site-header__inner {
    padding-top: var(--space-8);
    padding-bottom: var(--space-8);
  }

  .site-header__toggle {
    display: inline-flex;
  }

  .site-header__nav {
    position: absolute;
    inset-inline: 0;
    top: 100%;
    background-color: var(--color-surface);
    box-shadow: var(--shadow-md);
    border-top: 1px solid var(--gray-100);
    transform-origin: top;
  }

  .site-header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-12) var(--space-16) var(--space-16);
    gap: var(--space-8);
  }

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

  .site-header__nav-item--cta {
    width: 100%;
    margin-left: 0;
    margin-top: var(--space-4);
  }

  .site-header__cta {
    width: 100%;
    justify-content: center;
  }

  /* By default, nav is visible when no JS (progressive enhancement). When JS runs, it will add .js-nav-collapsed */
  .js-nav-collapsed .site-header__nav {
    display: none;
  }

  .js-nav-open .site-header__nav {
    display: block;
  }
}

@media (min-width: 769px) {
  .site-header__nav {
    position: static;
    box-shadow: none;
    border-top: none;
  }
}