Accessibility contrast issues on admin account creation form

Field elements and help texts have very low contrast values on the admin account creation form. The contrast issue is present in both stable and the new beta versions.

Start at the admin account creation form in both the stable and beta versions, then inspect the field elements and help texts with a contrast checker. Compare the rendered styles to identify the affected elements; done means the reported contrast issues are corrected in both versions and the form remains usable.

Written by the indexing model from the issue text.