All solutions

Hello!, good people... How do i apply a certain height/width so it matches with the solution image but without make it too big for mobile users? or too small for desktop users... (Should i even use a certain Height/Width?) or should i have had use any kind of shrink property that shrinks at different screen sizes that i dk off? And how do i vertically center it? i thought it was centered but is not T -T

I found difficult to center the design vertically. Im not sure if i centered the design as it should or as i could be centered, i created a container with a specific heigth and then i centered using flex box. I would like to know if it was necessary to add a general left, right, bottom and top margin. I insted centered everithing and applied an specific size to the desing.