Don’t let the title bar overflow into body

We have a fixed header that looks really broken if it overflows on
smaller screens. This change effectively hides the demo indicator on
small screens.
Get rid of the chapter positions (0/5 things)

These don’t do what the original designed hoped for, which was to 
progressively show completion of the course. There is no way to complete
a chapter.
Move the descriptions below the videos

The video content is more important than the description
Kill that little cloud that’s on top of my videos

That thing is on screen all the time and it’s distracting.