CSS Div nehmen die verbleibende Bildschirmhöhe

height:100vh;
/* 1vh is 1% of the browser size. With 100vh you can fill the complete height */
/* if you want the div to fill not only the size of the browser, but */
/* the complete website then use this: */
position: absolute;
height: 100%;
width: 100%;
Homely Hawk