In the head section, there is the , the , the , and the . Please note that favicons should be saved in the format. Furthermore, they will not display in without a (in other words, they won't be visible in until you ).

Fundamental to localized control of a website are and . Classes are deeply flexible. They can be used to apply formatting to thanks to (which is why we often use them with ). Ids, on the other hand, are . An id is a (hence the name), so they are used when one element needs , but you don't want the rest of your page to be affected by the .

As , images often represent the . Simply put, they are not as easy to as other elements. However, they marked a significant improvement for the and are a hallmark of the . They are efficient information delivery systems that represent concepts otherwise incomprehensible. With regards to , you'll likely need not worry about them unless you're using them for an image-intensive site.

Reviewing preprocessors creates a unique problem. We talked about them pretty late in the semester, but they are best when implemented of a project. The reason for this disparity is where the learning curve lies. You have to understand CSS as a style language in order to get any mileage out of . Thus, for this review, we begin with the files in order to show how they work with the CSS concepts. We've talked about modularity, and how the file architechture is laid out . There is the index, our , main.css, the file (which is quite large), main.scss (the file that is being processed into a ), mixins.scss (which contains, unsurprisingly, ), and stylevars.scss (which holds the we are using).