Change post title font size in mobile but not desktop

I have been struggling to change the post title font size for mobile devices without it impacting desktop. With long titles on mobile the font fills 1/3 of the screen. If I change it the post title font goes tiny on desktop.

Is there a way to have the best of both?
Thanks
Chris

Hi

Try this css in theme panel > custom css: http://screencast.com/t/yFwWucb5e

@media (max-width: 767px){
.single .entry-title {
font-size: 20px!important;
}
}

Thanks!