How do I limit the angle adjustment of an object?

You have a weapon that is pinned to the player. The weapon gets its angle set every tick to the position of the mouse.

How can I then give the weapon an angle limit, where no matter how much the player moves the mouse around, the rifle won't follow outside the angle of 0 to 90?

I've been stuck on this for a while as I'm out of ideas, so any help would be greatly appreciated.

If angle is greater than 90, set to 90. Specifically it could be if angle is clockwise from 90, then set to 90.