Having trouble getting clever CSS to run in IE8? Trying to use webfonts/@font-face and only some of them are being applied? Make sure you don’t have css psuedo-selectors in there, else IE8 dies.

i.e., if you have a list of classes/css selectors having a style applied to them, such as:
[css].modal h2, h1:not(.title), .prod_message .figure h2 {
color:orange;
}[/css]
then the entire section is ignored in IE8 due to the
[css]h1:not(.title)[/css]
entry.

I’ve not been able to track this one down for MONTHS and suddenly I get a new brand of coffee and it all makes sense. Come back to us, IE8, you are once again welcomed.