- 🇺🇸United States bmcclure West Virginia
I'm ashamed that it took me 3 years to get back to you, I'm so sorry to leave you hanging!
I'm assuming you either figured this out or gave up already, but if not, or if anyone else stumbles across this issue looking for an answer, I think the best reference for altering the CSS is the css/float_labels.css file within the module itself.
That has all of the default styling, so anything you want to override, just make sure to use a more specific selector (e.g. add either a parent class or a sibling class to the .float-labels-wrapper selector).
I can try and assist further if you do still need help, just let me know what you'd like to do with the CSS!