CSS in Depth

Chapter 9. Modular CSS

This chapter covers

• Emerging problems as a project grows
• Organizing CSS into modules
• Preventing escalating selector specificity
• Surveying popular CSS methodologies

In parts 1 and 2, we looked at the intricacies of CSS and the tools it provides for laying out elements on the page. We’ve made sense of the box model, margin collapsing, stacking contexts, floats, and flexbox. You’ll need these skills, particularly when you first set out on a new project. In the world of software development, however, you’ll spend a great deal of time not only writing new code, but also updating and adding to existing code. In CSS, this brings with it an entirely new set of difficulties.

When you make changes to an existing stylesheet, those ...