-How can I change or customize the EPG Guide background colors on a PC browser?

I would love to watch TV on my PC browser, but the Channels interface is all white with small letters!
**---How can I change or customize the EPG Guide background colors on a PC browser?

You can not. At present, there is no theme or customization skins.

You can zoom in with any browser, by doing Ctrl and + keys.
Browsers also have in their own settings text zoom settings...u can increase that.

If you want a page to be dark, or black, u can install a browser extension, such as Dark Reader, that changes websites to dark mode, it has various tweaks and things. I use it and it works very well, for most things.