you didn't look much.
under STYLING you have 2 buttons to 'Activate…' IDs of list and input field elements.
technically they're not classes, but they will suit your requirement to customize the fields
I looked much and I activated the ID's. When I activate ID's I can style each li, input and label individually. My question was, and I clearly wasn't clear enough, if I could set class="personal_info" (set red background i.e.) on some input fields and class="business_info" (for black text) in some other fields in the same form.
If I add Text only (no input) there was a field to set the class for that text. I wanted to do the same thing if I added a selectlist or singleline.
The thing with the ID's are that if I, for some reason,had forgot one input field on top of the form and already have set the style.css, I had to change the ID's in style.css because the ID's on the front change if I add or remove fields in the form. I wanted to be able to set classes to fields so I can change the form without having to change in style.css.
Have I explained my question enough?