Pseudo-elements and pseudo-classes in CSS definitive guide

Pseudo-elements and pseudo-classes in CSS: Definitive Guide

In CSS, pseudo-elements and pseudo-classes are powerful tools that allow us to select elements and apply specific styles to them. In this definitive guide, we will learn what pseudo-elements and pseudo-classes are, how to use them correctly and some practical applications.

What are CSS pseudo-elements?

Pseudo-elements allow us to add content or styles to an element without modifying its HTML structure. They are used to create visual effects or apply special styles to specific parts of an element.

There are several pseudo-elements, such as "::before" and "::after", which allow us to add content before or after an element. For example, we can use "::before" to add an icon before each item in a list.

ul li::before {
  content: "⭐";
}

We can also use pseudo-elements to apply styles to the first letter or line of an element. For example, we can use "::first-letter" to make the first letter of a paragraph larger or a different colour.

p::first-letter {
  font-size: 2em;
  color: red;
}

What are CSS pseudo-classes?

Pseudo-classes are selectors that allow us to select elements based on their state or position on the page. They allow us to apply styles to specific elements only in certain cases. For example, we can use the pseudo-class ":hover" to apply a style when the cursor is over a link.

a:hover {
  color: blue;
}

Another common pseudo-class is ":nth-child", which allows us to select elements based on their position within a container. For example, we can use ":nth-child(2n)" to apply a style to every second item in a list.

li:nth-child(2n) {
  background-color: lightgray;
}

Practical Applications

Pseudo-elements and pseudo-classes have many practical applications. For example, we can use "::before" in conjunction with generated content to add icons or decorations to elements without modifying their HTML.

We can also use pseudo-classes to apply styles to visited links, to forms when they are in an error state or to elements inside an active container.

Conclusion

In short, pseudo-elements and pseudo-classes are powerful tools in CSS that allow us to select elements and apply specific styles. They allow us to add content or styles without modifying the HTML structure and apply styles based on states or positions. Learning how to use pseudo-elements and pseudo-classes correctly can help us to create more sophisticated and dynamic designs.

So don't hesitate to explore and experiment with pseudo-elements and pseudo-classes in your CSS projects!

For more information and examples on pseudo-elements and pseudo-classes, please visit this link.