When smartphones and tablets first became popular, website developers could create separate mobile versions of their websites, which meant managing two separate websites. Responsive web design $($RWD$)$ technologies enable the developer to create one website that presents differently, depending on the device, platform, and even the screen orientation. Websites developed today typically employ a mobile$-$first strategy, in which 'they first consider the smallest screen size when determining layout and content. The goal of RWD is to create a website that has a positive UX$,$ regardless of who is using the website and on which device.

Do This: Visit a website on at least two devices that have different screen sizes. Make a note of the differences on each for content, media, and navigation. In what ways did the website designer employ a mobile$-$first strategy? Is the website easy to use on all devices? Which do you prefer? Why?