The problem occurred due to an incomplete CSS attribute.  In the style sheet was:

a:hover{
00CC00
}

so we changed it to:

a:hover{
color: #00CC00;
} 

Unfortunately if you press save while your CSS is incomplete or incorrect it will cause this error.  In the future we will be adding a CSS parser to this page so that this issue no longer occurs but in the mean time be careful when you hit save.