Dark and high contrast themes don't render hyperlinks or card text correctly

[v-kydela]

Version

4.10.0

Describe the bug

The text for hyperlinks and cards is unreadable when using the dark theme or high contrast theme.

To Reproduce

Steps to reproduce the behavior:

1. Have a bot send a hyperlink
2. Have a bot send a card with text outside of buttons
3. Switch to dark theme or high contrast theme
4. Observe that the text is unreadable

Expected behavior

All themes should use appropriate colors for all elements so that the text adequately contrasts with the background

Screenshots

Additional context

There are likely other cases of unreadable text besides just these two, so a thorough search would be appreciated. I suspect the solution would be in CSS.

[bug]