How Does Writing CSS Differ From Writing HTML?

As we write CSS these are the type of questions we might ask ourselves:

• Should the layout of the text be in a single or double column?
• Should we use a different font color for the header?
• How should the same content appear differently on a desktop versus a mobile device?

All of the questions above deal with the aesthetic considerations of the page. These are the concerns of the presentation layer (CSS).

As a contrast, let's consider the type of questions we might ask ourselves as we write HTML:

• Does the order of items within a list matter? Should it be a numbered list?
• Should we wrap a list of links inside a navigation tag?
• Is this the most important header in the whole HTML document?

The last few questions deal with structure, hierarchy, and meaning. These are the concerns of the content layer (HTML).

When we write CSS, we focus on aesthetic and display considerations. When we write HTML, we focus on structure, hierarchy, and meaning.