I have been trying to scour for ways to earn some hats while I come across this bug. The badge window goes out of the screen at the bottom and the modal's scroll still won't let me see the last badge's description at the bottom.
Considering my monitor is a "HD-ready" monitor (1366x768px). It might be reasoning enough that you did it based on 1080p resolution and above resolutions possibly.
How about changing the css (changing top: 65px to 0) by adding the appropriate resolution breakpoint?