Terminal applications don't cover the entire terminal

I've been researching this for a couple hours so far and I can't seem to find a solution that works and isn't 10 years old so I figured I'd ask again. I'm using awesome and Alacritty, and when I use, for example, emacs in the terminal, the emacs theme doesn't cover the entirety of the terminal.
I'm fairly sure that the issue has something to do with alacritty resizing based on characters instead of pixels or something like that, but I can't seem to fix it. I've tried change the gaps in ~/.config/awesome/rc.lua, I've tried changing font sizes in rc.lua, alacritty.yml, and in emacs, all with varying degrees of success.
I've also tried installing i3, and testing on that, because my main pc runs i3 and doesn't have this issue at all, but that doesn't change anything. All help is appreciated. Look closely at the bottom of the terminal window, you'll see a dark grey bar. That's the issue I'm talking about.