What is css programing

CSS: Cascading Style Sheets

Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in HTML or XML (including XML dialects such as SVG, MathML or XHTML). CSS describes how elements should be rendered on screen, on paper, in speech, or on other media.

CSS is among the core languages of the open web and is standardized across Web browsers according to W3C specifications. Previously, the development of various parts of CSS specification was done synchronously, which allowed the versioning of the latest recommendations. You might have heard about CSS1, CSS2.1, or even CSS3. There will never be a CSS3 or a CSS4; rather, everything is now CSS without a version number.

After CSS 2.1, the scope of the specification increased significantly and the progress on different CSS modules started to differ so much, that it became more effective to develop and release recommendations separately per module. Instead of versioning the CSS specification, W3C now periodically takes a snapshot of the latest stable state of the CSS specification and individual modules progress. CSS modules now have version numbers, or levels, such as CSS Color Module Level 5.

Key resources

If you’re new to web development, be sure to read our CSS basics article to learn what CSS is and how to use it.

Our CSS learning area contains a wealth of tutorials to take you from beginner level to proficiency, covering all the fundamentals.

Our exhaustive CSS reference for seasoned Web developers describes every property and concept of CSS.

Looking to become a front-end web developer?

We have put together a course that includes all the essential information you need to work towards your goal.

Tutorials

Our CSS Learning Area features multiple modules that teach CSS from the ground up — no previous knowledge required.

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.

This module carries on where CSS first steps left off — now you’ve gained familiarity with the language and its syntax, and got some basic experience with using it, it’s time to dive a bit deeper. This module looks at the cascade and inheritance, all the selector types we have available, units, sizing, styling backgrounds and borders, debugging, and lots more.

The aim here is to provide you with a toolkit for writing competent CSS and help you understand all the essential theory, before moving on to more specific disciplines like text styling and CSS layout.

With the basics of the CSS language covered, the next CSS topic for you to concentrate on is styling text — one of the most common things you’ll do with CSS. Here we look at text styling fundamentals, including setting font, boldness, italics, line and letter spacing, drop shadows, and other text features. We round off the module by looking at applying custom fonts to your page, and styling lists and links.

At this point we’ve already looked at CSS fundamentals, how to style text, and how to style and manipulate the boxes that your content sits inside. Now it’s time to look at how to place your boxes in the right place in relation to the viewport, and to each other. We have covered the necessary prerequisites so we can now dive deep into CSS layout, looking at different display settings, modern layout tools like flexbox, CSS grid, and positioning, and some of the legacy techniques you might still want to know about.

This module provides links to sections of content explaining how to use CSS to solve common problems when creating a web page.

Reference

• CSS reference: This exhaustive reference for seasoned Web developers describes every property and concept of CSS.
• CSS key concepts:
  • The syntax and forms of the language
  • Specificity, inheritance, and the Cascade
  • CSS units and values and functional notations
  • Box model and margin collapse
  • The containing block
  • Stacking and block-formatting contexts
  • Initial, computed, used, and actual values
  • CSS shorthand properties
  • CSS Flexible Box Layout
  • CSS Grid Layout
  • CSS selectors
  • Media queries
  • Animation

  Cookbook

  The CSS layout cookbook aims to bring together recipes for common layout patterns, things you might need to implement in your sites. In addition to providing code you can use as a starting point in your projects, these recipes highlight the different ways layout specifications can be used and the choices you can make as a developer.

  Tools for CSS development

  • You can use the W3C CSS Validation Service to check if your CSS is valid. This is an invaluable debugging tool.
  • Firefox Developer Tools lets you view and edit a page’s live CSS via the Inspector and Style Editor tools.
  • The Web Developer extension for Firefox lets you track and edit live CSS on watched sites.

  Meta bugs

  See also

  • CSS demos: Get a creative boost by exploring examples of the latest CSS technologies in action.
  • Web languages to which CSS is often applied: HTML, SVG, MathML, XHTML, and XML.
  • Stack Overflow questions about CSS

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  CSS Introduction

  Here we will show one HTML page displayed with four different stylesheets. Click on the «Stylesheet 1», «Stylesheet 2», «Stylesheet 3», «Stylesheet 4» links below to see the different styles:

  Why Use CSS?

  CSS is used to define styles for your web pages, including the design, layout and variations in display for different devices and screen sizes.

  CSS Example

  body <
  background-color: lightblue;
  >

  h1 color: white;
  text-align: center;
  >

  p font-family: verdana;
  font-size: 20px;
  >

  CSS Solved a Big Problem

  HTML was NEVER intended to contain tags for formatting a web page!

  HTML was created to describe the content of a web page, like:

  This is a heading

  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.

  To solve this problem, the World Wide Web Consortium (W3C) created CSS.

  CSS removed the style formatting from the HTML page!

  If you don’t know what HTML is, we suggest that you read our HTML Tutorial.

  CSS Saves a Lot of Work!

  The style definitions are normally saved in external .css files.

  With an external stylesheet file, you can change the look of an entire website by changing just one file!

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  What is CSS?

  

  Click on the «Try it Yourself» button to see how it works.

  CSS Syntax

  A CSS rule consists of a selector and a declaration block:

  The selector points to the HTML element to style (h1).

  The declaration block (in curly braces) contains one or more declarations separated by semicolons.

  Each declaration includes a CSS property name and a value, separated by a colon.

  In the following example all

  elements will be center-aligned, red and have a font size of 32 pixels:

  Example

  Same example can also be written like this:

  External Style Sheet

  A CSS style sheet can be stored in an external file:

  mystyle.css

  External style sheets are linked to HTML pages with tags:

  Example

  My First CSS Example

  This is a paragraph.

  Inline Style

  Example

  My First CSS Example

  This is a paragraph.

  This is a paragraph.

  This is a paragraph.

  Cascading Order

  If different styles are specified for HTML elements, the styles will cascade into new styles with the following priority:

  • Priority 1: Inline styles
  • Priority 2: External and internal style sheets
  • Priority 3: Browser default
  • If different styles are defined on the same priority level, the last one has the highest priority.

  Example

  Multiple Styles Cascades into One

  Try experimenting by removing styles to see how the cascading stylesheets work.

  Try removing the inline first, then the internal, then the external.

  CSS Demo — One HTML Page — Multiple Styles!

  Here we will show one HTML page displayed with 4 different stylesheets.

  Click on the Stylesheet buttons (1-4) too see the page displayed with different styles.

  Full CSS Tutorial

  This has been a short description of CSS.

  For a full CSS tutorial go to W3Schools CSS Tutorial.

  For a full CSS reference go to W3Schools CSS Reference.

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