How can I create a custom background and set the text colors?

The capability to do this was introduced by Netscape in version 1.1 of that product. By now, many web browsers support it.

Please note: if your page is difficult to read, people will not read it. Please use the background attributes tastefully unless it is your intention to alienate your readership. A separate FAQ <URL:> on the subject is maintained by Mark Koenen. Consult that document for more information.

World Wide Web FAQ