What is the bug in HTML

Question

When I remove the Letters it doesn't show my Control table and on putting the letters back it show the table
I don't know what is the bug
https://code.sololearn.com/WVJuNq3T0LW4/?ref=app
https://code.sololearn.com/WHWko6tv878O/?ref=app

Answer 1

Because your margin top is -135 so it is not in the screen. But when you add letters, you make it getting down so you can see it.
Try to add only two letters and see the result 😉.