Chapter 1, Harness the Power of Sass for Responsive Web Design, starts with the easiest walkthrough you'll ever read on how to install Sass; then we learn how to make Sass "watch" our SCSS files. Then, there are easy-to-understand explanations about basic Sass concepts such as variables, mixins, arguments, nesting, partial files, the @import directive, source maps, and Sass comments. We also learn to automate vendor prefixing and automatically compile our SCSS files with Prepros. We talk about creating mixins to address media queries as easily as possible, considering how content defines the breakpoints.

Chapter 2, Marking Our Content with HTML5, clarifies that HTML is a markup language, not code. Then, we talk about the most used HTML5 elements that allow us to markup our content semantically. Improving the accessibility of our builds with ARIA roles is also something we address in a simple way. We also talk about the different meta tags required for RWD, and then we have an example that brings everything together.

Chapter 3, Mobile-first or Desktop-first?, demystifies why and when mobile-first or desktop-first should be used. With examples, we will learn how to retrofit a site with Adaptive Web Design, and of course, with RWD. We will learn about Respond.js and conditional classes in order to support legacy browsers when building mobile-first.

Chapter 4, CSS Grids, CSS Frameworks, UI Kits, and Flexbox for RWD, helps us understand what a grid is, how to use it, and why. With this understanding, we can make sound decisions when building a website or web app. We also create a custom CSS grid both with the floats technique and then by using Flexbox. We will use conditional classes again to address old browsers, and with the help of a small script, we can take care of the quirks from IE10 with an .ie10 specific selector.

Chapter 5, Designing Small UIs Driven by Large Finger, shows how usability and accessibility play a major role in this chapter. We also find explanations about the different sizes of our target zones, the location of our controls (links, buttons, form fields, and so on), and the touch zones in different devices. There are also three examples on how to create a menu button plus three more examples on mobile navigation patterns.

Chapter 6, Working with Images and Videos in Responsive Web Design, is one of the most interesting chapters of this book because images in RWD are a "thing". We will talk about different ways to serve different images with the <picture> element and the srcset attribute. Making videos responsive with CSS, jQuery, and JavaScript is also addressed in this chapter. We also learn about using vector-based files such as icon fonts and SVGs.

Chapter 7, Meaningful Typography for Responsive Web Design, talks about using relative units being ideal because they provide scalability, and this is what RWD is all about. The golden egg in this chapter is that we will learn how to use the Modular Scale to create a harmonious typographic scale. We will also use Flowtype.js to increase the legibility of our copy.

Chapter 8, Responsive E-mails, shows that e-mails are opened more on mobile devices than on desktops; that responsive e-mails have more engagement on mobile devices than nonresponsive ones; and that people click on e-mails on desktops more than on mobile. We will also create an e-mail template as an example. We'll learn to use a CSS reset block to normalize those quirky e-mail clients and learn that the best width for e-mails is not more than 600 pixels.

All these chapters have CodePen demos.