How do I make this CSS effect work in Squarespace?

Hi folks!

I have a sentence in a text block on my site where I'd like the last word in it to "rotate" through different words. I found a CSS example on the web: https://jsfiddle.net/n5dLdgor/1/ that illustrates exactly what I want to do (although my word will always be at the end of the sentence). Even the style of the transition is what I want. But given that text is in blocks with IDs on Squarespace, I'm wondering how to alter this code to get it to work in Squarespace CSS/Code Injection (especially because it needs to identify and change only the last word in the sentence in the text block). Thanks in advance for your help!

Thank you so much!

The first one was exactly what I needed (and her video is SO good at explaining how to implement it and how to tweak details). 

Best, JV