If you remember, we talked about grids in the first chapter. Grids help a lot with Responsive design, but their use does not stop there. Designers have used grids since print design, for books, publications, and especially magazines. To simply define it, a grid system is a system that helps designers structure their design, content, and imagery, and make it more readable and manageable.
Understanding grids is very important because they will help you design in proportion, balancing between the elements in your design, organizing modules, and sections. And more importantly, it will help the user navigate with the consistency and familiarity of your design grid:
The Grid system website (http://thegridsystem.net/), is a very useful tool for every grid system, and is a must-know.