Transparent Mobile Header & Slider Height on Mobile

Hello, On my computer, the header of my website is transparent and the slider fills the entire vertical space of the browser window. On my phone, the header is solid white in both portrait & landscape, and the slider does not fill the vertical space in either portrait or landscape orientations.

Is there a way to make the phone experience match the tablet and computer behavior and have a transparent header with a slider that fills the vertical space of the browser window?