Online Marketer – Adding a flexible logo image

Hi, I’m using Online marketer theme (Awesome theme btw) and have added a #top-header image as logo that works quite well… until I see it in a mobile device. I added the following code using a smaller-proportionate image but still have no change. Any help would be greatly appreciated:

@media screen and max-width 460px {
#top-header {
background-image:url(‘https://www.globalsitesolutions.ca/wp-content/uploads/2014/06/logo-mobile.png’);
margin:auto;
}
}