Modify banner position and site of Twenty-Sixteen Theme

Hello,
I’m very new in wordpress. I’m trying to customize the Twenty-Sixteen theme and would like to customize the site header (banner).
In style.css it named as “site-header”. I would like to modify the site-header from left, right, so that site-header is equal to “sidebar widget-area” and from upper side 42px smaller.

I’ve tried many different changes inside the style.css, but nothing seems worked.

Any help in this regards is highly appreciated.

Best Regards,