Use sufficient color contrast for brand colors to comply with WCAG 2

Continuing the discussion from Transition Brand Guide:

Thanks for the transition guide. One suggestion: Try to use colors that validate according to WCAG 2.0 (at least level AA) - brand colors are difficult to change afterwards.

Colors that are needed for the brand and do not have sufficient contrast should be explicitly marked as pure decorative colors that should not be used for text or as background for text.

At the moment, the light blue does not validate at all, orange and green only validate for large text and level AA.

Further reading: (especially 1.4.3 and 1.4.6)