/* Header layout */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(245, 251, 255, 0.95);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--color-border-subtle);
}

.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 */
.header-brand {
  flex: 0 0 auto;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--color-text);
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 0.9rem;
  background: radial-gradient(circle at 10% 0%, var(--color-accent-mint), var(--color-primary));
  color: #ffffff;
  font-weight: 700;
  font-size: var(--font-size-sm);
  box-shadow: var(--shadow-sm);
}

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-lg);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.brand-subtitle {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

/* Navigation */
.site-nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--space-6);
}

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

.nav-link {
  position: relative;
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 0.35rem 0;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent-mint));
  transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--color-primary-dark);
}

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

.nav-cta-group {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.nav-cta {
  font-size: var(--font-size-xs);
}

.nav-cta-secondary {
  padding-inline: 1.1rem;
}

/* Mobile toggle */
.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-2);
  border-radius: var(--radius-pill);
  padding: 0.45rem 0.85rem;
  border: 1px solid rgba(148, 163, 184, 0.4);
  background-color: rgba(255, 255, 255, 0.9);
  color: var(--color-text);
}

.nav-toggle:focus-visible {
  outline: 2px solid var(--color-accent-mint);
  outline-offset: 2px;
}

.nav-toggle-box {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.18rem;
  width: 1.1rem;
}

.nav-toggle-bar {
  width: 100%;
  height: 2px;
  border-radius: 999px;
  background-color: var(--color-neutral-700);
  transition: transform var(--transition-base), opacity var(--transition-base), translate var(--transition-base);
}

.nav-toggle-text {
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* Toggle active state */
.site-header.is-nav-open .nav-toggle-bar:nth-child(1) {
  transform: translateY(4px) rotate(45deg);
}

.site-header.is-nav-open .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.site-header.is-nav-open .nav-toggle-bar:nth-child(3) {
  transform: translateY(-4px) rotate(-45deg);
}

/* Responsive behavior */
@media (max-width: 960px) {
  .site-nav {
    position: fixed;
    inset-inline: 0;
    top: 3.75rem;
    border-top: 1px solid var(--color-border-subtle);
    background: rgba(245, 251, 255, 0.98);
    backdrop-filter: blur(18px);
    flex-direction: column;
    align-items: stretch;
    padding: var(--space-4) var(--space-4) var(--space-6);
    gap: var(--space-4);
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transform: translateY(-8px);
    transition: max-height var(--transition-slow), opacity var(--transition-base), transform var(--transition-base);
  }

  .site-header.is-nav-open .site-nav {
    max-height: 420px;
    opacity: 1;
    transform: translateY(0);
  }

  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
  }

  .nav-link {
    padding: 0.35rem 0;
    font-size: var(--font-size-base);
  }

  .nav-cta-group {
    flex-direction: column;
    align-items: stretch;
  }

  .nav-cta,
  .nav-cta-secondary {
    width: 100%;
    justify-content: center;
  }

  .nav-toggle {
    display: inline-flex;
  }
}

@media (max-width: 600px) {
  .brand-subtitle {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-nav {
    transition: none;
  }
}