Ways to color the alert for obligatory fields in a form?

Hi, the color for obligatory field alerts is somewhat unnoticeable sometimes. Is there some idea on how to make it more visible if a customer hits the send button and forgot to fill in any of the obligatory field inputs? Maybe color it contrasting the main color of the page

There are hover states that alert the user if the form hasn’t been filled out correctly, but for now changing the colour state of the container as a warning is not yet possible.