[data-site-header] :is(.site-header__nav--left, .mobile-menu__links) :is(a, summary) {
  text-decoration: none;
  text-underline-offset: 3px;
}
@media (hover: hover) {
  [data-menu-underline="true"] :is(.site-header__nav--left, .mobile-menu__links) :is(a, summary):hover {
    text-decoration: underline;
  }

}