There is an accessiblity issue with the link color in the dark theme introduced in JDK-8342705. It appears that the color used for links does not have enouth contrast to the surrounding text color.

https://docs.acquia.com/web-governance/link-text-color-must-contrast-sufficiently-its-background-color

This can be checked using online tools such as the WebAIM link contrast checker:

https://webaim.org/resources/linkcontrastchecker/