When switching between LIVE and TEST environments, or when having both open in different tabs, the difference should be more obvious than the tiny TEST mention in the top left box.
The overall site color could be different, or have a large banner, or anything that you can't miss.
The goal is to avoid mistakes where you would change something LIVE without realizing you're on the LIVE site.
Thank you so much for the suggestion. We'll definitely find a way to make a distinction more explicitly.