Brooklyn theme semi-sticky header for mobile

[cabinfruit]

Hey all, can I get instructions and code to make the header become semi-sticky so on scroll up it pops ups? 

Additionally, I have it as a transparent header right now (as it sits at top of site nicely) but I want the semi-sticky header to have a black background. 

Lastly - is it possible to shrink the logo on the semi-sticky header? Obviously on landing I like the larger logo (used code to increase it actually) but as a semi-sticky header (of which really I just am trying to give access to navigation)  I don't need it as large and would probably even replace it with a small logo/icon instead of full brand mark. 

Thanks!

Lorenzo 

@Dallas  @

[dmwwebartisan]

@cabinfruit 

Please share screenshot what do you want or reference site.

Thanks!