I wrote my own
SyntaxHighlighterEngine class that using the Atom Highlights package.
The markup generation step works well, but to apply custom stylesheets the only way that I found is to add my own styles to
/webroot/rsrc/css/core/syntax.css file and then rebuild the celerity map.
It is works now, but I want to know is there ant way to add custom syntax highlighting styles and not to modify the source files of Phabricator.