How to add to react-flexbox-grid to lein project?

[stjo15]

In my project.clj, I have this dependency:
[cljsjs/react-flexbox-grid "1.0.0-0" :exclusions [cljsjs/react cljsjs/react-dom]]
And :source-paths ["src/clj" "src/cljs" "src/cljsjs"]
I'm trying to import this in my css:
@import (inline) "cljsjs/react-flexbox-grid/production/react-flexbox-grid.min.inc.css";
I'm building the project, but nothing appears in the cljsjs folder.
I'm unfamiliar with lein, did I miss something?
Thanks!