I try to change de css also for the logo, & it worked like this :
/header font size for tablet/
@media(max-width: 768px){
#header .top-header .header-logo{
font-size:23px!important;
}}
/header font size for mobile/
@media (max-width:525px){
#header .top-header .header-logo{
font-size:12px!important;
}}