@font-face not working

Double period (..) means you go up one folder and then look for the folder behind the slash. For example:

If your index.html is in the folder html/files and the fonts are in html/fonts, the .. is fine (because you have to go back one folder to go to /fonts). Is your index.html in html and your fonts in html/fonts, then you should use only one period.

Another problem could be that your browser might not support .eot font-files.

Without seeing more of your code (and maybe a link to a live version of your website), I can’t really help you further.

Edit: Forget the .eot part, I missed the .ttf file in your css.

Try the following:

@font-face { 
font-family: Gotham;
src: url(../fonts/gothammedium.eot);
src: url(../fonts/Gotham-Medium.ttf); 
}