I made some minor changes to the default stylesheet to have blocks of code no longer overflow the edge of the page.
Changes were based on the stylesheet I found at
http://www.bigbold.com/snippets/stylesheets/posts.css.
I added in the following:
pre { border: 1px solid #333; padding: 6px; overflow: auto; margin: 0px 1%; width: 95%; }
Thanks to the Snippets public code repository.
Changes and suggestions welcome!