Add additional clues when a required field is not filled in

Related to WCAG 2.1 criteria:

• level A criteria 1.4.1 use of color
• level AA criteria 3.3.3 error suggestion

When a required field is not filled in a form, Web UI uses color and an increased stroke width to convey the information.

This is not accessible enough.

Recommendation to fix
RULE :
Any information conveyed by color MUST be accompanied by a programmatically-discernible text alternative.

Any information conveyed by color MUST be accompanied by a visible alternative (text, image, etc.) that does not depend on color for meaning.

HOW TO FIX:
Error identification must not rely on color alone, such as only outlining the field in red or changing the field label to red, to communicate the error.

Fix this issue by using ONE or BOTH of the following techniques:
1. Provide a list of error messages that include the field name at the top of the page.
2. Provide an inline form error message that includes the field name or is associated with the field or both.