Responsiveness
What is responsiveness?
Put simply, responsiveness is when a website responds to certain conditions. For example, if you're on a smaller screen like a mobile phone, a responsive website will automatically change the layout of the page to suit the smalle screen.
That's what we just did here!
Try visiting this website on a mobile phone and see what happens to the menu. Pretty cool, ey?
If you don't have your mobile phone to hand, you could just shrink this window in your browser, then keep shrinking it to see what happens.
Just like in previous steps, This page is covered in more detail on my blog post, Making A Website 04 - Responsiveness.
You can download the source code for this step (and all other steps) from the downloads page.