Sometimes we make oversights like a ‘ & ‘ ampersand in the url var value that is telling php that we want to stop and add another variable.
similar to mypage.php?something=hello&anotherthing=world
my title was “Html & Css part….”
it read what came after the &, as a new variable and broke my page.
Sometimes the teacher gets taught 
_aq
You keep on learning, any way, you are by far the best free teacher I’ve ever met. Keep the good work, and i hope i can make a donation really soon ;D
(by the way i couldn’t understand a thing about programming until i watched your videos!)
P.S. sorry for my english, is not my native lenguge