This page demonstrates how a callback function can be
used with Adapt.js to change the class of the HTML tag.
Visible at: 0px to 760px
Visible at: 760px to 980px
Visible at: 980px to 1280px
Visible at: 1280px to 1600px
Visible at: 1600px to 1920px
Visible at: above 1920px