Align logo to center: Sticky menu on mobiles

Hello,
Both the theme and this forum are great.

For my website, I was able to sort out most of the issues.

There is just one minor niggle:
On mobiles, when the site first loads up, the logo is in the center.
As one begins to scroll down, the logo suddenly jumps to the left.

How can I change this behavior? I want to keep the desktop site unchanged (In the desktop site, the logo is always on the left, with the menu on the right).

Thanks,
Siddharth.