In this chapter, we covered the most important aspect of Bootstrap—its grid system. We learned how to use the grid system to structure a page, and how the grid system is actually implemented using breakpoints and media queries. As a result, we learned how to leverage Bootstrap to create a responsive web page and how to target specific content to specific displays. In addition, we also discovered a very nice feature of all the layout-specific utility classes—the fact that they can also be used as mixins and are indeed used as mixins within other Bootstrap classes. Leveraging these classes when we start writing custom style rules for MyPhoto will surely come in useful. As our understanding of Bootstrap is now sufficient enough to allow us to structure a basic page, let's proceed to the next chapter in which we will build the layout for our MyPhoto page.