Sometimes you want a section to fill the entire screen, no matter what the screen size is. You can control this with vh, or view height. The number before it is a percentage, so if you want it to fill 100% of the browser, you would set it to 100. You might set it to a value like 85% to accommodate a fixed navigation menu. Create a class for the container and apply the amount of vh you want it to have. One thing you may need to tweak is the media query value for specific screens or orientations like phones in portrait mode. Imagine stretching a landscape image to fit portrait mode. That just wouldn’t look good.
.fullheight { height: 85vh; }