CSS interpretation in Firefox

I am experiencing some differnences between Firefox and other browsers regarding general display of text in Course Presentation. I have created this example to illustrate how a long lists of text can look ok in Chrome and other browsers but deviate in Firefox. https://h5p.org/node/175035

This could cause problems with partial missing text when the whole slide is used/filled with text: https://ndla.no/nb/node/129553?fag=52234