How can I change the RED color of the red rectangle that comes up with the "This field is required." message within it?

How can I change the  RED color of the red rectangle that comes up with the "This field is required." message within it when a user does not fill out a required field?

Thank you.

I can see you have also opened a different thread related to the same question, it can be found here: https://www.jotform.com/answers/1049082 

On that thread you will find the steps  to change the background color of the field container, if you would like to change the background color of the required message container as well then you would need to inject this CSS code: 

.form-line-error .form-error-message{

    background-color:orange;

}

.form-line-error .form-error-message .form-error-arrow {

    border-bottom-color: orange;

}

Replace the "orange" color with the one you need, this guide will help you to inject the code to your form: https://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes 

Hope this helps.