This is a trick I just discovered on my Windows 10 computer. I use Windows' default dark theme and have a dark mode add-on for my Chrome browser, but some websites don't react well to the add-on, and there are some websites like HN that refuse to go dark unless you switch a flag in Chrome. So I just made a discovery for Windows.

Go to settings, then Ease of Access, High contrast, and turn on high contrast. A waiting screen will appear for a few seconds.

Here's what HN normally looks like for me: https://i.imgur.com/orTRml1.png

And here's what it looks like after (on the high contrast menu, I changed the color of text to be the same as the color of disabled text): https://i.imgur.com/yCKq0wc.png

Another example. Here is cnn.com before: https://i.imgur.com/ycMs0ME.png

And here it is after: https://i.imgur.com/9oNDxeH.png