Poor contrast in "required" keyword in dark mode

[rebekaburnett]

Poor contrast in "required" keyword in dark mode

To reproduce this:

1. Install the Wave plugin (Web accessibility evaluation tool) in Chrome
2. Open your redocusaurus website here: https://redocusaurus.vercel.app/examples/using-single-yaml/#tag/pet
3. Change to dark mode.
4. Click the small W icon in the header to turn on Wave. You will see the contrast errors listed on the left.
5. Scroll down to find the "required" keyword/label (see attached image, "required") and click on the red icon to see the code.

Please note that there are many other contrast errors and it would be great if you fixed those, too. I will try to override any that I can, but without style names, it's difficult. Maybe you could create style names and let people override them manually.