I'm trying to do a simple thing in CSS

I have a header tag and inside that a couple of h tags. So, in order to have a responsive design I do

height:auto;

inside the header tag, so it will automatically stretch to contain the h tags. Right?

But does not work, headeris just a line in the top of the page. t should stretch to contain the titles, right?

What am I missing?

Is it a good practice to put CSS in the h tags and not style header at all? So h tags will be like the header in user's eye?

Thanks in advence

Check it here