CSS not updating

I am creating a new website on a subdirectory on my current tierrapermanente.com/wp and I want to customize my theme, i know a little of css so i went to edit the style sheet but the changes did not show. I read most of the solution (refresh, f5, trying in another computer, clear cache, stop using cache programs…) non of this work. I even checked from a ftp server (fillezilla) if the changes in the style sheet had been made and they were there. Please help