28 Feb Two libraries that provide both of these in synch are big-app.co.uk and big-app.co.uk Let's get started adding these into a big-app.co.uk application (try. big-app.co.uk big-app.co.uk Build Status. Reveal CSS animation as you scroll down a page. By default, you can use it to trigger big-app.co.uk animations. But you can. when using delay with big-app.co.uk only a few of the big-app.co.uk classes keep elements invisible until scroll past. They are highlighted blue.