Changing the form’s error message and design

Hi,
how can I change Caldera’s form error message (This value is required) and how can I design it?
I want to design it with a blue background, but I want the background to be at the length of the text (meaning I might have to work with span).

I found the class:

.caldera-grid .has-error .checkbox, .caldera-grid .has-error .checkbox-inline, .caldera-grid .has-error .control-label, .caldera-grid .has-error .form-control-feedback, .caldera-grid .has-error .help-block, .caldera-grid .has-error .radio, .caldera-grid .has-error .radio-inline, .caldera-grid .has-error.checkbox label, .caldera-grid .has-error.checkbox-inline label, .caldera-grid .has-error.radio label, .caldera-grid .has-error.radio-inline label {

and I was able to change the text color and the background color but I wasn’t able to control the background’s with and I can’t replace the text.

Thanks