Header doesn't resize / show on mobile?

Hey everyone!

So I’ll keep it brief. I’m using the Twenty Thirteen theme, and my website is http://www.westernidentity.info. My problem is that on my PC, my website looks perfect, but on mobile, the theme just removes the header entirely, and there is no option to change this.

I’m kind of surprised such a major theme would not have a way of incorporating the header on mobile. As my header is my logo and site title without it my page is essentially worthless. Several other themes I’ve tried also just removed the header on mobile or worse, failed to resize it and just zoomed in to a random part of it.

Is it really so difficult to have a header look the same on mobile and desktop? Is there something obvious I’m missing here? This wasn’t the case with my last website but now I’ve forgotten what theme I used.

If anyone can recommend me a solution or a theme that does resize the header that would be great. Thanks!