What does that tell you, and is there a remedy for that?
Now that we know what is causing it.
I was told it is not reproducible on Firefox but easily on Edge and Chrome.
Solution is the same: width:
calc(50% + 1px); or,
When you did yours, how come you didn’t use 51% and went with calc instead? @PaulOB
With YouTube Code Removed, No Gap Visible.