How to fix text width inconsistency between Chrome and Firefox

Question

I am working in this simple example: https://jsfiddle.net/mz7tr5kj/2/

I am truncating the h3 and box__description with CSS, which works just perfect on chrome. On FF it does not. The width is overflow the parent container and does not truncate.

I want the behavior of chrome to be exactly on FF?

Env:

OS: MacOS

Chrome Version 73.0.3683.103 (Official Build) (64-bit)

FF 66.0.3 (64-bit)