In the preceding examples, only the grid columns were defined. This should give you a good and realistic impression of how grids work and how to use them. A complete grid code also defines responsive containers and row classes. Most grids will also have so-called gutters between their columns. A gutter (mostly fixed) is a space that separates columns. This also means that a width spanning two columns include one gutter.
In Chapter 4, Avoid Reinventing the Wheel, you have learned to reuse Less and prebuilt mixins; you can do the same for grids. It won't be necessary to write the complete code yourself. Frameworks such as Twitter's Bootstrap, the Golden Grid System (http://goldengridsystem.com/), or Less Framework 4 (http://lessframework.com/) will provide you with all the Less code and mixins you need. Some of these frameworks will be discussed in further detail in Chapter 6, Bootstrap3, WordPress, and Other Applications.