LightSlider - decrease hight

can somebody please help - I´m looking for a way to get a flexible hight for the LightSlider. I`m using the sora article theme.
The width of the bg picture should be 100%.
In the LS custom css I set: .grav-lightslider .panel-bg {background-size: contain; background-position: center;}, but it seems to be a fixed hight… thanks.