I downloaded the Default CSS file (Admin, Advanced Layout Options, Default CSS file) by doing a Save As...
I pulled the file into Komodo (it's what I use to edit Perl and other languages). I made some changes to the styles (I changed several items font-size:7.5pt to font-size:medium just to see what would happen).
I saved my file (still has the name of default.css). I went to the Administrative File Uploads, browsed for my file, and clicked Submit.
I went back to the Advanced Layout Options and I have the Test It button (which I clicked and a new page promptly popped up for me). Unfortuntely, NONE of the font sizes changed. After tweaking the sizes upward multiple times (and doing multiple uploads and tests), I finally picked something ridiculous just to make sure I could see it (the next raid style went from 16pt to xx-small). Still no love....
I think I must be missing a step somewhere that lets my website know to use the new uploaded .css file.
now ofcourse Change the names accordignly: fate by what your guildsites name is (u can see that in the administrative file uploader, u can see a link: /settings/fate/files/ so where it says fate for me it will say something else for u and then change colors.css to what ever name your css is.
then upload the css to administrative file uploader, go to Advanced layout options Upload the Layout.html file (click submit) and only then u will see the changes u made to the Font sizes/colors