CSS Class and ID selectors - name

Question

The name of the CSS Class and ID selectors cannot start with a number.
#2Xlarger doesn't work; #X2larger works fine.
For example:
https://code.sololearn.com/WwVPb6EFmUY5

Answer 1

nice work !!☺

Answer 2

Danke schön gemacht

Answer 3

I am working on an expanded version.
I have included in this example a list with the restricted characters in the name of the CSS class and ID
https://code.sololearn.com/Wb12H7uPw7X6