Currently, all of the questions are in red text except for "Which other schools are you considering?" which is in black text. Once a question is answered, the text changes from red to black except for the first question (Applying for Grade), which changes to green.
The form builder doesn't have a way to customize the validation treatment for fields. If the prompt/field is required, it is returned with "red" validation and if optional (or not required), no validation is shown.