One of the web trends these days is the Pinterest-ish, responsive, varying height tile design. Examples of this are Pinterest (of course), NYPL.org, and some others. Doing this in pure CSS is a bear if not completely impossible due to CSS's rather interesting handling of element height.
Design & Development
Here is list of some great AR apps to use in your library: You can get all of them for free on the App store.
Chromeville; Coloring Pages
ColAR - Coloring Pages
The Brain AR
Google Apps: What can you do with it?
The tools I find most useful in libraries are: Drive, Docs, Slides, Forms, Sheets, Sites and of course Gmail and Calendar. There are many others.
The best applications I’ve found for the tools include:
TechEx Websites 101 Week Two: Website builders, Blogging Programs, & Content Management Systems
After learning how to create screencasts, you might be interested in learning how to edit tutorials. Some librarians opt to simply re-record their screencasts when interfaces change or record many times until they finally get it right.
Screencasting tools capture your screen and your voice. Though, they can be used to make tutorials, I use free screencasting tools with some email reference questions.