Introduction to CSS

Introduction to CSS

• CSS stands for Cascading Style Sheets.

• CSS is used to style and design HTML elements, enhancing the look and feel of web pages.

• CSS was developed by Håkon Wium Lie, the Chief Technical Officer (CTO) at Opera Software.

• It was initially proposed in 1994 and officially published in 1996.

• The current version of CSS is CSS3, which introduced numerous new features and capabilities to web design.

CSS Syntax

The syntax of CSS consists of a selector and a declaration block. A typical CSS rule looks like this:

selector {
  property: value;
}

For example:

h1 {
  color: blue;
}

This CSS rule will turn all <h1> elements blue.

Cascading

Cascading refers to the order in which CSS rules are applied to elements. CSS follows a set of rules to determine which styles to apply when multiple rules target the same element. The key factors in cascading are:

• Specificity: More specific selectors override more general ones. For example, an ID selector is more specific than a class selector.
• Priority: When two rules have the same specificity, the one defined later in the stylesheet takes priority.

Note: CSS code is written in a key-value pair format. The key represents the property, and the value defines the style applied to the selected element.

• Style: CSS rules used to apply styles to elements on a webpage.
• Sheet: A digital document containing CSS rules, typically linked to an HTML document.