Minify css

I enabled CSS compression on Template Advanced settings.
But when I run Google Pagespeed it says many css files are not compressed:
Minifying http://www.casino-online.bz/templates/gk_news2/css/override.css could save 3KiB (50% reduction).
Minifying http://www.casino-online.bz/templates/gk_news2/css/mobile.css could save 2KiB (17% reduction).
Minifying http://www.casino-online.bz/templates/gk_news2/css/tablet.css could save 1.3KiB (17% reduction).
Minifying http://www.casino-online.bz/templates/gk_news2/css/small.tablet.css could save 796B (25% reduction).
Minifying http://www.casino-online.bz/…templates/gk_news2/css/small.desktop.css could save 606B (26% reduction).

Did I have to enable something else to get all css files minified?

Hi,
because build-in compression system in template settings don't compress those files.
It's how it was designed ;(

Hey Oscar, can you suggest me one (safe and good) extension that could minify css and html?

In theory I could, but I'm not sure if all compressed mobile css will still work.
You can also manually compress those mobile / tablet css (online tools) and replace files, it will reduce their size and you don't have use addcional plugins.

Thank you Oscar. I thought that too, but someone on internet suggested that it is more safe to use a plugin to manage compressed files. Anyway I can do as you suggested to me. They are only 5 files.
There are some plugins that combine all css in one, so the server requests decrease and the website is more fast.

If I join all the css files into one file (on gknews2 template) then the website will continue working as usual?

if I join all the css files into one file (on gknews2 template) then the website will continue working as usual?

I never tried with gk responsive templates, so I don't want to lie.
You don't loose anything, use plugin compress and check.
If not alternative methods are also good.