After I upgraded to the latest SyntaxHighliger (2.0.296) I noticed that the font size of the code section is a little bit too small to my taste. But there is not an UI option to change it.
So I went to the source code and located the style sheet where the font parameters are set.
To change the default font-size, you will need to modify the following CSS file: [your WordPress install root path]/wp-content/plugins/syntaxhighlighter/syntaxhighlighter/styles/shCore.css. Locate the following class:
.syntaxhighlighter span { margin: 0 !important; padding: 0 !important; border: 0 !important; outline: 0 !important; background: none !important; text-align: left !important; float: none !important; vertical-align: baseline !important; position: static !important; left: auto !important; top: auto !important; right: auto !important; bottom: auto !important; height: auto !important; width: auto !important; line-height: 1.1em !important; font-family: "Consolas", "Monaco", "Bitstream Vera Sans Mono", "Courier New", Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; }
And change the font-size to 1.05em or the size you prefer. Note that this setting is extremely sensitive and typically a 5 percent of increase is enough. Since prefer the Courier font better, I also swapped it with the default “Consolas”.