Interactive Rating Component - Vanilla JS, CUBE CSS, accessibility

With this project I have tried to keep accessibility in mind; although I'm unsure if it is the correct / ideal implementation. The select buttons are a part of a fieldset with role="radiogroup" and a legend that is visually hidden. As the card is a form, I included error checking so that if the form is submitted without selecting a rating, then an error message is displayed. I have not looked into fully checking accessibility but I think that the error message would be announced when using a screenreader because of the role="alert" attribute:

<strong class="alert" id="error-msg" role="alert" hidden>Select a rating from 1 to 5</strong>

This seems like a sensible solution as it means the error message is styled to match the card rather than being a browser-styled popup as with other form inputs / elements.