EasyBlog styles.css Overrides

Hello there,

I have made some changes to the ...default/css/style.css file and the ...elegantwhite/css/style.css file, now I want to put these files in an override folder to avoid a loss during updates.

In addition I have created a folder to my Joomla Template which is called protostar2 in my case. So I placed these two files in the following folders:

.../templates/protostar2/html/com_easyblog/themes/default/css/styles.css
.../templates/protostar2/html/com_easyblog/themes/elegantwhite/css/styles.css

but this has no effect, did I misunderstood something?
The Documentation do not help me further.