There are 2 packages which provide only a CSS resource. These are @atlaskit/css-reset and @atlaskit/reduced-ui-pack. The latter provides styles for some specific HTML+CSS patterns that mimic some of the common AtlasKit components. They don't have all the variants available to their React counterparts. They should allow you do some nice page layouts, with forms and buttons. There's no JS requirement so it will work with any tech stack (even React if you just need some light-weight forms).