Most of this site is "assembled" using the Website Meta Language in something which should be valid Strict XHTML 1.1 with a valid CSS. The CSS is a modified version of the one which is used on esr's website (he himself tooks it from somewhere else...).
The design of this site should be compliant with Web standards, so it should be viewable with any browser. However, as I use neither Windows nor Mac OS X, I cannot test the design with Microsoft Internet Explorer or Apple Safari. Anyway, if you are using Internet Explorer, as it is notoriously not standard compliant and moreover it usually contains unpatched security flaws, you should consider switching to a safer alternative, like Firefox (it's free!).