Basic CSS: 100% zoom

What does it mean Browser zoom should be at 100%?

Due to browser implementation differences, you may need to be at 100% zoom to pass the tests on this challenge.

I watched the video but he doesn’t make any mentions about 100% zoom.

It should be your default zoom.

If you are using chrome. You can check it my clicking on settings icon on top right window (3 vertical dots). It will show your zoom level.