Mantra Theme Menus

Copy menu.html.twig from Classy.

Add attach_library('mantra_theme/menu').

mantra_theme.libraries.yml

menu:
  css:
    component:
      css/drupal/component/menu.css: {}

menu.css

ul.menu {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem .5rem;
    padding-left: 0;
}