Get a slider to fit resolution of screen

Hey there.

I think I have a fairly simple problem that I can’t seem to find the solution to. Maybe I’m just tired and it’s time to go to bed. ^^

How do I make the initial Tab Slider adapt to whatever resolution so the image fill upp the screen?
If I try to change height to “%” instead of “PX” then it all gets compressed in a weird way and the same with “Auto”.

Thanks a lot!

Could you please share your public link!