Bug on "Learn HTML & CSS: Part l"

Somewhere on part 5. of learning HTML & CSS: Part 1 the fake web page on the right side of the screen went blank, and whenever I completed a instruction it would automatically finish the other instructions even though I didn’t do them. I exited the entire page and went back on and it was still the same, if anyone has any answers they would be appreciated.

Maye you could give us the HTML and CSS code you are using…?