accessibility bugs of lightbox overlay

[stefan-schubert-sbb]

After integration of datatrans lightbox our accessibility test results in different problems related to the usage of that lightbox:

• Inputs are not accessible in linear direction top down
• in high contrast mode the light box has no visible frame
• focus styling is not strong enough and only slightly visible
• error message are not related to the payment method -> generic messages used
• focus of page, which embeds lightbox, is reseted -> original focused element is not refocused after closing box
• page scroll position is not correctly restored after closing lightbox