Maybe the most popular design technique is the responsive behavior. In the last few years several HTML/CSS frameworks have appeared to make programming tasks much easier for frontend developers.

As designers, it is useful to know how these frameworks function in order to provide the correct specifications to the developers. A grid system provides a common reference to communicate the layout aspects of your designs.

Two of the frameworks most used at the time of writing this book are Zurb Foundation, which also has a reduced version for emails, and Bootstrap, a project that was originally created by two Twitter workers and is currently open source. Both the systems are based on the use of columns and have a strong community that supports them, in addition to numerous tutorials and examples that explain how to use them.

It is worth following the evolution of standards such as Flexbox (https://www.w3schools.com/css/css3_flexbox.asp), a new layout mode in CSS3, and CSS Grid (https://www.w3.org/TR/css -grid-1/), which introduces a two-dimensional, grid-based layout system.