Some Of The Sites I Use Have White Lettering On Dense Black Background.

[Henry1865]

How do I reverse this?

[jno]

I don't know about reversing it but you can always make the type bigger and easier to read (ctrl +); crtl 0 will return you to normal size.

[TheWinner]

does this help?

[Buenchico]

You've got Windows Dark Mode selected. You need to change it to Light Mode.

Right-click on your desktop.

Select 'Personalise' and then click on 'Colors'.

In the box where it says "Choose your mode', click on 'Dark' and change it to 'Light'.

[Henry1865]

Thanks Buenchico for the advice.