Hi Olga,
Thank you for your explanation. I have managed to follow the procedure however, there is something strange happening. Both on my other staging site and live website when i save, afterwards the same css codes re-appear in revslider-static-css.
It looks like that I cannot properly save. Could you please advise? did you do something else in order to save the change?
If necessary I could provide you access to the other staging and live website.
Thanks.
F.