/* Header styles build on base.css */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-fixed);
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-gray-200);
  transition: box-shadow var(--transition-base) var(--ease-in-out), background-color var(--transition-base) var(--ease-in-out);
}
.site-header.is-scrolled {
  box-shadow: var(--shadow-base);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
}
.brand a {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-primary);
  font-size: 1.5rem;
  color: var(--color-text);
}
.brand a:hover {
  color: var(--color-primary-hover);
}

/* Menu toggle */
.menu-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border: 2px solid var(--color-gray-300);
  border-radius: var(--radius-full);
  color: var(--color-text);
  background-color: var(--color-white);
  transition: all var(--transition-base) var(--ease-in-out);
}
.menu-toggle:hover {
  border-color: var(--color-sage);
  color: var(--color-sage-dark);
  box-shadow: var(--shadow-sm);
}
.menu-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}
.menu-toggle .icon-close { display: none; }
.menu-toggle[aria-expanded="true"] .icon-open { display: none; }
.menu-toggle[aria-expanded="true"] .icon-close { display: inline; }

/* Primary nav */
.primary-nav { width: auto; }
.menu {
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-6);
  margin: 0;
  padding: 0;
}
.menu li { margin: 0; }
.menu a {
  display: inline-flex;
  align-items: center;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-full);
  color: var(--color-text);
  text-decoration: none;
  transition: background-color var(--transition-base) var(--ease-in-out), color var(--transition-base) var(--ease-in-out), transform var(--transition-fast) var(--ease-in-out);
}
.menu a:hover {
  background-color: var(--color-sand-light);
  color: var(--color-text);
}
.menu a:active {
  transform: translateY(1px);
}

/* Mobile layout */
@media (max-width: 768px) {
  .header-inner { position: relative; }
  .primary-nav {
    position: absolute;
    top: 100%;
    left: 0; right: 0;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-gray-200);
    box-shadow: var(--shadow-base);
  }
  .menu {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }
  .menu li { border-top: 1px solid var(--color-gray-100); }
  .menu li:first-child { border-top: 0; }
  .menu a { padding: var(--space-4) var(--space-6); }

  /* Progressive enhancement: hide menu only when JS is enabled */
  html.js .primary-nav { display: none; }
  html.js .primary-nav.is-open { display: block; }
}

/* Desktop layout */
@media (min-width: 769px) {
  .menu-toggle { display: none; }
  .primary-nav { position: static; box-shadow: none; border: 0; }
}