1. Grab a lightweight CSS framework like Milligram (there are a bunch of them) and add it so the forms will be styled in a more modern way.
2. Test on mobile. For me the layout of the current forms shows up wrong, it doesn't take the full screen width and labels in the example form run over other elements.
Also thanks for for the mobile test feedback. Can I ask what mobile device you tested on? Such data points would be really useful to me.
I actually did test on my phone first, Android/Chrome and _in landscape_ it appeared usable. The PDF also produced OK. It was not an _amazing_ experience but compared the PDF form experience I had it was a delight. I don't consider a phone when I have to fill out a form but in an emergency it would have been possible.