a11y: Low contrast on links in dark mode

[luk-str]

Hey Amberley,

Thanks for this great project! 🔥

Just wanted to let you know that I ran WAVE on the start-testing page and found an issue with very low contrast on some links.

It happens only on "Lesson hosted on egghead.io" links that appear under the embedded videos and only in dark mode. It appears they just use default styling and hence become dark blue (or dark purple after visit) and almost disappear against the background.

See screenshot below:

Let me know if you'd like assistance with fixing the issue. I'd be happy to contribute 🙂