Definitely not a stupid question! Foundation is a UI framework, not a CSS framework (that also applies to Bootstrap). That means (some of) its components are made of HTML, CSS and JS. For instance, Reveal modals include methods to open and close them. The same applies to Dropdowns, Tooltips and Accordions. That’s why including Foundation in a VueJS application requires including its JavaScript. You could just use the CSS, but that would mean re-implementing components functionality from scratch. Ideally, it should be possible to connect VueJS with Foundation JavaScript by creating Vue components which are wrappers for Foundation components and can be initialized with props (take a look at this gist, which uses Foundation 6.4). Foundation 7 will remove jQuery and things should become definitely simpler. In the meanwhile, if you are looking for a CSS-only framework, you could take a look at Bulma.