JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
You can change the font size and color of the form warning by injecting a CSS code into your form:
font-size: 13px !important;
color: green !important;
You can change the 13px size to some size you want and change the font color green to any color you like.
In addition, you can try changing the style of your error when you edit your form and click Designer.
Under COLOR SCHEME, click properties just right after Simulate error state
Then you can change your error style
If you have questions, please do let us know.