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What is CSS? Learn web development MDN

They are separated with a colon and delineated with a semi-colon. CSS is easy to learn and understand, but it provides powerful control over the presentation of an HTML document. CSS3 became a W3C recommendation in June 2012 and builds on older versions CSS.

css definition

They are used to set lengths, paddings, margins, align elements and so on. Even if any other rule in the CSS defines the color, this inline style rule is going to be applied. We increase this value when we have an element selector. If you have more than one element selector in the rule, you increment accordingly the value stored in this slot.


It can be used to create a layout — for example, turning a single column of text into a layout with a main content area and a sidebar for related information. Have a look at the links in this paragraph for specific examples. In the Introduction to HTML module, we covered what HTML is and how it is used to mark up documents. Headings will look larger than regular text, paragraphs break onto a new line and have space between them. Links are colored and underlined to distinguish them from the rest of the text.

css definition

They are additional keywords that we can add to the media attribute of link or the the @import declaration, to express more conditionals over the loading of the CSS. In this section we’re going to first introduce media types and media feature descriptors, then we’ll explain media queries. If all items are defined as 1 and one is defined as 3, the bigger element will shrink 3x the other ones. When less space is available, it will take 3x less space.


CSS is an amazing tool, and in the last few years it has grown a lot, introducing many fantastic features like CSS Grid, Flexbox and CSS Custom Properties. This article will help you get up to speed with CSS and get an overview of the main modern features you can use to style your pages and apps. CSS is often quickly dismissed as an easy thing to learn by developers, or one thing you just pick up when you need to quickly style a page or app. Due to this reason, it’s often learned on-the-fly, or we learn things in isolation right when we have to use them. This can be a huge source of frustration when we find that the tool does not simply do what we want. Pseudo Selectors can be used to narrow down a selection with certain rules.

css definition

But I suggest to always use them for consistency and to avoid errors if you add another property and forget to add the semicolon on the previous line. Next, the person that knows CSS from a few years but hasn’t had the opportunity to learn the new things in it. We’ll talk extensively about the new features of CSS, the ones that are going to build the web of the next decade. CSS is often considered like a secondary thing to learn, especially by JavaScript developers. They know CSS is not a real programming language, they are programmers and therefore they should not bother learning CSS the right way.

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We might want to choose this one on western languages, while word-break has special treatment for non-western languages. Speaking of CJK text, the property line-break is used to determine how text lines break. I’m not an expert with those languages, so I will avoid covering it.

When tags like , and color attributes were added to the HTML 3.2
specification, it started a nightmare for web developers. Development of large
websites, where fonts and color information were added to every single
page, became a long and expensive process. The style sheet with the highest priority controls what does css do for a web page 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. This further decouples the styling from the HTML document and makes it possible to restyle multiple documents by simply editing a shared external CSS file.

css definition

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