Mobile Logo resizing

I'm trying to increase the size of the Logo on the mobile version to exceed the 150 px. I'm using the following code but after I refresh a couple of times it goes back to the preset size

.header .header-title--use-mobile-logo         .header-mobile-logo img {
     max-height: 250px
}

Any help would be highly appreciated

Can you share link to your site? We can check easier