For example, if multiple selectors target the same element in a document, which rules apply? When two or more rules conflict on the same element, the more specific one applies. CSS instructions are added to HTML documents in order to style the document. The tag must be placed within the head element of an HTML document. Each rule consists of a selector and a declaration block.

What is CSS

But this data has to be arranged and formatted into a form that’s understandable by end-users who have a wide range of technical experiences and abilities. If you are learning web development, you will come across terms like HTML, CSS, and JavaScript. The HTML above is not styled, because the element classes don’t follow a strict grandparent, parent, and child order. Until April 2023, no browser understood the nested CSS syntax. You required a build step with a CSS preprocessor such as Sass, Less, or PostCSS to transform the nested code to the regular full-selector syntax.

Changing the default behavior of elements

The style sheet with the highest priority controls the content display. Declarations not set in the highest priority source are passed on to a source of lower priority, such as the user agent style. Some properties can affect any type of element, and others apply css web development only to particular groups of elements. The selector points to the HTML elements you want to style. The declaration block contains one or more declarations separated by semicolons. Before using CSS, all of the stylizing had to be included into the HTML markup.

What is CSS

If you want to use it with CRA and are looking for assistance, this blog will show you how. All we need to do is import our theme and styles into our component and then pass them to our elements. A good feature of Vanilla Extract is its easy-to-use syntax.

Do You Still Require a CSS Preprocessor?

CSS-in-JS was widely adopted by the React community a few years ago. We can say that the majority of React developers are using CSS-in-JS libraries. Say you want to remove the underline from only certain links in all states.

What is CSS

CSS was developed by W3C in 1996 for a rather simple reason. HTML element was not designed to have tags that would help format the page. You were only supposed to write the markup for the web page. It’s important to understand the difference between HTML and CSS because they are two very different languages that serve two very different purposes.


So for knowing Web Development, learning CSS is mandatory. In years past, there were select web designers that refused to use CSS for the design and development of websites, but that practice is all but gone from the industry today. CSS is now a widely used standard in web design and you would be hard-pressed to find anyone working in the industry today who did not have at least a basic understanding of this language. Websites are comprised of a number of individual pieces, including images, text, and various documents.

What is CSS

So in your example document, you should find that the in the third list item is now purple, but the one inside the paragraph is unchanged. You can continue to work in styles.css locally, or you can use our interactive editor below to continue with this tutorial. The interactive editor acts as if the CSS in the first panel is linked to the HTML document, just as we have with our document above. Save your HTML and CSS files and reload the page in a web browser. The level one heading at the top of the document should now be red. If that happens, congratulations — you have successfully applied some CSS to an HTML document.

Cascading Style Sheets Explained In a Video Tutorial

I agree to receive email communications from Progress Software or its Partners, containing information about Progress Software’s products. I acknowledge my data will be used in accordance with Progress’ Privacy Policy and understand I may withdraw my consent at any time. Leonardo is a full-stack developer, working with everything React-related, and loves to write about React and GraphQL to help developers. We’re going to create a new variable named todoButton for the button as well. When a web application is run without requiring any additional downloads, this is referred to as zero runtime. Users can access and use modern web applications quickly and easily without having to wait for additional resources to be loaded or installed, which is critical for modern web apps.

For example, you could take a look at the MDN reference to the Backgrounds and Borders module to find out what its purpose is and the properties and features it contains. In that module, you will also find a link to Specifications that defines the technology . In the above example, the CSS rule opens with a selector. This selects the HTML element that we are going to style.

An Introduction to Native CSS Nesting

It has a great type-safe styling API and requires no runtime. This is a simple but effective demonstration of the power of Vanilla Extract. One thing to note is that Vanilla Extract cannot be used with plain create-react-app, but it can be used with Craco.

A document is usually a text file structured using a markup language — HTML is the most common markup language, but you may also come across other markup languages such as SVG or XML. CSS works in conjunction with HTMLand is directly responsible for dictating color, background, text color, font, positioning and additional features to the web browser. In this case, a .child1 element inside .parent1 has a specificity of 002, because it matches the two classes (#parent2 is ignored). Its selector is less specific than the native option and has a greater chance of being overridden in the cascade. They would all work in this simple example, but you could encounter specificity issues later with more complex stylesheets.

What is the difference between HTML and CSS?

CSS describes how elements should be rendered on screen, on paper, in speech, or on other media. CSS is a rule-based language — you define the rules by specifying groups of styles that should be applied to particular elements or groups of elements on your web page. CSS nesting is one of the most useful and practical preprocessor features. The browser vendors worked hard to create a native CSS version which is similar enough to please web developers. There are subtle differences, though, and you may encounter unusual specificity issues with complex selectors, but few codebases will require a radical overhaul. By including CSS styles in JavaScript code rather than a separate CSS file, the bundle size increases.