Sorry but all the syntax highlighting of my blog seems to be broken.
I think it comes from my plugin, SyntaxHighlighter Evolved, and I'm working to find the issue.
Sorry for the inconvenience, I hope to find a solution soon !
EDIT : Problem is (half) solved.
I found the root cause : another plugin I installed yesterday : Jetpack with a misplaced tag.
Now I'll need some more time to fix the issue :)