This box will turn to pink if the viewing area is less than 600px
This box will turn to orange if the viewing area is greater than 900px
This box will turn to blue if the viewing area is between 600px and 900px
This box will only apply to devices with max-device-width: 480px (ie. iPhone)
Your current viewing area is: less than 600px between 600 - 900px greater than 900px
Adapted from a tutorial by Web Designer Wall