Problem with Mobility on mobile with a header

[carisma_sensei]

Now that I got my header up as you can see on my journal, it looks great on PC which is where I mostly use Dreamwidth. But on mobile it's obviously not responsive (the css is, the header isn't).

Is there anything I could do to fix this, or should I rather learn to live with it? hahaha. If this were transmogrified, I know the content and the header would have the same measures when zooming in and out. But for this, since it's customized for mobile viewability, I don't know what I could do. So any input would be appreciated.

Thanks in advance!