Fluid Layout, Flexbox, and Responsive Images

At the end of the last chapter, we reminded ourselves that the three core tenets of responsive web design are fluid layout, media queries, and flexible media. We spent Chapter 3, Media Queries – Supporting Differing Viewports, learning all about media queries. Now we know how to wield them to change a layout at a particular "breakpoint."

In this chapter, we will focus on the other two pillars of responsive web design: fluid layout and flexible media. By the end of this chapter, we will be able to ensure any designs we code can flex easily between breakpoints, responding to the confines of their container.

Eons ago, in the mists of time (well, the late 1990s), websites were typically built with their widths defined as percentages. These percentage-based widths fluidly adjusted to the screen and were known as fluid layouts.

In the years after, in the mid-to-late 2000s, there was an intervening...