Scaling / GUI size incorrect

[K0-RR]

Environment

• OS: Ubuntu 24.10
• web-greeter version (output of web-greeter --version): 3.5.3
• LightDM version (output of `lightdm --version): 1.30.0

Bug description

I'm using web-greeter on two PCs, and on this one the sizing seems incorrect.

Steps to reproduce

Have a 21:9 (3440x1440) monitor, I guess.

Expected behavior

Proper UI size

Screenshots

default window size

Changing the window size to 3000x1340:

And 2999x1340: