It looks fine, honestly. My only suggestions are to:
Put your HTML/CSS in a text file and read it in. Don't put massive text blocks in your python code.
Your comments are weird, they should be like: """ The html sheet to be created and customized. """
Did you copy and paste this a lot: ################################################
If you find yourself copy/pasting the same thing over and over, store it as a variable. That way if you wanted to use 50 #s instead of 55, you only have to change it in one place.
Quote from reddit user MrBernoulli