Documentation in any Open Source project is seen as the Holy Grail. It's great to have but somehow never quite fulfills the needs of the users.
Joomla has an excellent documentation resource but I think it is fair to categorise these docs mainly as "reference" material and not "user guides".
Some people are able to open up a graphic editor and produce stunning original artwork for their web sites. I'm not one of those people. For me it's usually a case of searching the net in the hope of finding the perfect graphic that exactly matches my needs. Usually I fail in that search and end up with the closest thing I can find.
The web was meant to be read, not squished.
This isn't the way to test a responsive design.