Don't style generic <section>s in experiments
Add a friendlier experiment title

* Create experiment body and header styles
* Remove old Facebook and Twitter button styles, buttons have been
removed
* Remove experiment’s h1 styles
Fix parallax experiment in new layout

* Don’t use position: fixed, absolute is fine
* Tweak experiment region boundaries so that parallax can go right to
the edges
Tweak clock experiment for new layout
Fix 2d cube experiments in new layout
Tweak 3d cube experiment

* Prevent scrolling with up and down keys
* Tweak vertical spacing
Tweak sphere controls

* Position closer to top