.webform-submission-form .form-item .form-item--error-message {
  color:red;
}
.webform-submission-form input .error {
   animation: changeBorderToRed 6s linear forwards;
}

@keyframes changeBorderToRed {
    0%   {border-color: red;}
    70%  {border-color:var(--primary-colour);} /* Set the final border color here */
    100% {border-color: var(--primary-colour);}
}