If you need to customize the colors (or do more restyling) of validation messages in ASP.net MVC, the following snippet from a discussion on ASP.net forums should be useful: Add to Content/Site.css: /* styles for validation helpers */ .field-validation-error {     color: #b94a48; } .field-validation-valid {     ...

Just came across this validation error display in an MVC app I’ve recently started maintaining. The required input field validation seemed to not be localized, resulting in a mixed English and Greek (from the field’s Display name) message: Looking at the MVC model I noticed they were using [Required] attributes for the userName and password ...