/articles: glossary word popover escapes viewport

[bryceerobertson]

Popover should appear above the cursor if it's below a certain distance from the bottom of the viewport.

[LeMurphant]

I am also having the issue on Firefox, it's fine on Chrome

Chrome

Firefox

[bryceerobertson]

@LeMurphant looks like that's a different issue (the image being squeezed). I was referring to the fact that part of the popover box disappears from the screen if it's close to the bottom

[LeMurphant]

@bryceerobertson my bad, I should have listed it in #489 instead