How do I get rid of the space for the title/tagline after hiding them?

I’m experimenting with the Esplande theme, and the first thing I did was turn off the site title and tagline using the CSS:

#site-title, #site-description {visibility:hidden;}

However, that still left a big blank rectangle above my header image, so I tried:

#site-title, #site-description {text-indent:-9999px;}

But I still had the big blank area. I have no idea how to get rid of it.

Is there simple CSS I can add to remove the tons of space above my header image (but still leave a tiny bit, obviously)?

The site I’m experimenting on right now is: https://www.comicreviewdaily.com