Upfront CSS not getting applied

Trying to add CSS via Upfront but it doesn't seem to work. Added @media CSS inside the region CSS of Upfront, and also via Upfront Global CSS but it doesn't seem to work in both methods.

@media only screen and (max-width: 768){
.title h1{
font-size:61px !important;
}
}

It works fine when the CSS is added via custom CSS plugin. Looking for a CSS which works in Upfront, only for the specific page. Please check chat transcript for more info.