Change question underline/text area colours

Right now you can change the background colour of forms, but not the input underline/text area colours.

This is a problem if you also use the question styling option without background/shadows - your form can become difficult to read - e.g. https://paperform.co/templates/interview-release-form

Right now the only fix is to subscribe to the Agency plan, but this is overkill for a basic feature to make your forms legible.