I noticed that there are many tags for which the code language used for code highlighting is set to "none," which means that a question using one or more of those tags would not use any highlighting syntax. It would be better to have it set to "default," which normally works fine for languages using a C-like syntax (such as in the case of PHP and JavaScript), for XML, and HTML.
As normally the code snippets are in PHP, JavaScript, or HTML, the "default" option should work for most the cases, and it should be preferable to "none."