What is CSS?
Ever wonder how web pages have a specific look and feel with color, fonts, and layout? These features are part of the Cascading Stylesheet (CSS) language. It provides for the separation of the data in HTML from the styling of the data. Thus, developers can define the look of a webpage separately from the text it contains.
There are three ways to write CSS:
- Inline CSS: HTML element is styled;
- Embedded CSS: CSS rules are located in an HTML file; and
- External CSS: CSS is located in an external file. This makes the CSS code easy to maintain and reusable.
We'll look at each type in the following sections.
Browser support information
Once CSS has been specified then it is only useful for us in developing web pages if one or more browsers have implemented it. This means that the code has been written to turn the instruction in our CSS file into something that can be output to the screen. We'll look at this process more in the lesson How CSS works. It is unusual for all browsers to implement a feature at the same time, and so there is usually a gap where you can use some part of CSS in some browsers and not in others. For this reason, being able to check implementation status is useful.
The browser support status is shown on every MDN property page in a section named "Browser compatibility" (use this to check if the property can be used on your website). For example, the compatibility section for the CSS font-family property
is reproduced below.
