Typographically, preformatted text is not the same thing as code. Sometimes, a faithful execution of the text requires preformatted text that may not have anything to do with code. Most browsers use Courier and that’s a good default — with one slight adjustment, Courier 10 Pitch over regular Courier for Linux users. For example:
“Beware the Jabberwock, my son! The jaws that bite, the claws that catch! Beware the Jubjub bird, and shun The frumious Bandersnatch!”
Let’s keep it simple. Italics are good to help set it off from the body text (and italic Georgia is lovely at this size). Be sure to style the citation.
Good afternoon, gentlemen. I am a HAL 9000 computer. I became operational at the H.A.L. plant in Urbana, Illinois on the 12th of January 1992. My instructor was Mr. Langley, and he taught me to sing a song. If you’d like to hear it I can sing it for you.
— HAL 9000
And here’s a bit of trailing text.