Help on how to change the template style in gravity pdf

Hi guys, my name is Giuseppe and I have a question for you. Tell me the procedure for changing the style of the PDF template (I use zadani) of some fields I have in a form. I know html, css, and a little php. If in my form I have a text field with id 3 and an end-of-section field with id 5, explain to me how I could, for example, change the color of the text. Thank you in advance and I apologize for my English.