Having more of a WPF background, it’s hard for me to understand why in HTML/CSS it’s so difficult to create full-screen UIs. In WPF, with a relative small number of layouts, it’s easy to arrange and align anything anywhere. Align a panel to the bottom of the screen, centering panels inside other panels or overlapping panels is easy to implement and easy to understand.

Creating full-screen UIs in HTML has always been complicated. But the show continues even today when IE is just a medieval story and there are different systems (flexbox, grid) that are supposed to make things easier.