This article explains what the cascade is and the order in which CSS declarations cascade, covering cascade layers and origin type. Understanding origin precedence is key to understanding the cascade. You will find that you quickly learn some values, whereas others you will need to look up. The individual property pages on MDN give you a quick way to look up properties and their values when you forget or when you want to know what else you can use as a value. However, the web would be a boring place if all websites looked like that.
Development of large
websites, where fonts and color information were added to every single
page, became a long and expensive process. We go into details about cascading in Chapter 15, « Cascading and
inheritance. » Before that, there is much to learn about fonts,
space and colors. CSS has been designed to resolve conflicts between
style sheet rules like the one above. You can find the details in Chapter 15 , « Cascading and
inheritance. » In the example, it is « green, » but it could just as easily be blue, red, yellow, or some other color.
CSS = Styles and Colors
We
devote much of the rest of this book to explaining what you can do
with CSS. In this chapter, we begin by introducing you to the
basics of how to write style sheets and how CSS and HTML work
together to describe both the structure and appearance of your
document. In the pursuit of the question of “what is CSS”, visual examples are a great help. To that end, this next section will build on the cascading details provided in a more visual approach. Again, multiple styles have been applied to the single paragraph tag on the HTML document. Now the stylesheet has two instances of the paragraph element in place.
However, when the same value is to be set on all sides, listing it once will suffice. This is true both for padding and margin (as well as some other border properties, which are described in See Space around boxes. ). The last properties, font-variant and line-height, haven’t been widely supported in browsers up to now and are therefore not as commonly used yet. CSS was developed by W3C (World Wide Web Consortium) 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.
Video: CSS Introduction
Notice that the previous use of the paragraph element is still on the sheet. CSS is one of the most powerful tools a web designer can learn because with it you can affect the entire visual appearance of a website. 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. Each rule or rule-set consists of one or more selectors, and a declaration block. CSS (Cascading Style Sheets) is used to style and layout web pages — for example, to alter the font, color, size, and spacing of your content, split it into multiple columns, or add animations and other decorative features. This module provides a gentle beginning to your path towards CSS mastery with the basics of how it works, what the syntax looks like, and how you can start using it to add styling to HTML.
CSS can be used for very basic document text styling — for example, for changing the color and size of headings and links. 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. website development css cascading 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.
Author stylesheets
CSS, or cascading style sheets, is the designer’s link to a toolset that allows for truly amazing style options on an HTML document. CSS works by targeting HTML elements and applying style rules to define how they should be displayed, including properties like color, size, layout, and positioning. Every web page is affected by at least one style sheet, even if the web designer doesn’t apply any styles. This style sheet is the user agent style sheet — also known as the default styles that the web browser will use to display a page if no other instructions are provided.
Someone who finds red italic headings difficult to read may apply a different style sheet. Browser extensions like Stylish and Stylus have been created to facilitate the management of such user style sheets. In the case of large projects, cascading can be used to determine which style has a higher priority when developers do integrate third-party styles that have conflicting priorities, and to further resolve those conflicts.
CSS Example
CSS lets authors move much of that information to another file, the style sheet, resulting in considerably simpler HTML. And additionally, as more and more devices are able to access responsive web pages, different screen sizes and layouts begin to appear. Customizing a website for each device size is costly and increasingly difficult.
- This means that the CSS part of the web page didn’t load correctly or it doesn’t exist altogether.
- The HTML page rendered the paragraph element with the value of red instead of sea green.
- It was intended to allow web professionals to separate the content and structure of a website’s code from the visual design, something that had not been possible prior to this time.
- CSS allows the content to be optimized for more than one type of device.
- In the example, it is « green, » but it could just as easily be blue, red, yellow, or some other color.
The first gives it three property values to work with, one of which is the color of sea green. However, the next use of the paragraph element also gives it a color value as well. In the image below, you can see how the page will render with this code in place.
Support
This means that the HTML document then moved on to that one and took whatever was inside of it. The only property value it found was the color change to red. It applied this to the paragraph element and gave a final render that was seen above. Before addressing the interactions, we’ll define some key terms in the next few sections. The style sheet with the highest priority controls the content display.
This website provides tutorials with examples, code snippets, and practical insights, making it suitable for both beginners and experienced developers. We’ll go over each style briefly, for an in-depth explanation of each method, there will be a link below the overview. CSS is not technically a necessity, but you probably wouldn’t want to look at a web page that features only HTML elements as it would look completely bare-boned. That CSS addition will render the paragraph element on the page as shown below.
Only at Udacity
The modular nature of CSS means that styles can be reused in different parts of a site or even across sites, promoting consistency and efficiency. In the last set of examples you saw that the text color of the
links turned blue without that being specified in the style sheet. Also, the browser knew how to format blockquote and h1 elements
without being told so explicitly. Everything that the browser
knows about formatting is stored in the browser’s default style sheet and is merged
with author and user style sheets when the document is displayed. For those beginners just getting started with web design, a single direct question always seems to come up right away.
