Can't resolve "jumping header" issue, tried common fixes already

I'm trying to resolve this jumping header image before I get too far into several sites. These are in-progress:
— https://qgr.hzh.mybluehost.me/website_74f75ea8
— https://durfeycreative.com/

I thought I'd resolved this already:
The Theme Builder options are set: https://app.screencast.com/utNe5cIcZubzl .
And I've added CSS to define the #page-container padding-top and the #main-header top positioning:
https://app.screencast.com/uShVHDi3kKIJj

Any ideas?

Thanks!
—
Kurtis
Central Oregon, USA