"Non cercare di eseguire prima di poter camminare."
I think you are doing too many things which is not helping you to learn. Doing too many things, one after the other, and nothing working, is confusing for you and anyone who tries to help you.
First of all. Have you put a copy of the logo in this new theme's ( chilly_pepper folder?) You need to add all the images for your theme into the theme you are intending to use, and do this for every theme you use or intend to use, otherwise it will not show up because Moodle only looks in the theme folder it is using at any one time.
Also there are two areas where you need to add the code for the Logo. You have it right in theme_Mia, so if I were you I would stay with that theme and change the CSS slowly, a little at a time, until you get it just as you want it to look.
Also each theme has it's own set of stylesheets.Because you made a copy of formal_white your stylesheets will be fw_layout.css, fw_font.css and fw_color.css. In cafelite it's cafelite.css, in chilly_pepper it's styles.css.
By the way, Cafelite is not showing up in your site theme folder I have just checked this online. Normally one can see the header.html if you know how to, but there is nothing there on your site, there is not cafelite theme folder, so you have either renamed the file or put it in the wrong folder!
Hope this helps?