What is CSS?

  • CSS stands for Cascading Style Sheets
  • CSS describes how HTML elements are to be displayed on screen, paper, or in other media
  • CSS saves a lot of work. It can control the layout of multiple web pages all at once
  • External stylesheets are stored in CSS files

CSS Syntax

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

CSS selector

The selector points to the HTML element you want to style.

The declaration block contains one or more declarations separated by semicolons.

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

Multiple CSS declarations are separated with semicolons, and declaration blocks are surrounded by curly braces.

CSS Selectors

CSS selectors are used to “find” (or select) the HTML elements you want to style.

We can divide CSS selectors into five categories:

  • Simple selectors (select elements based on name, id, class)
  • Combinator selectors (select elements based on a specific relationship between them)
  • Pseudo-class selectors (select elements based on a certain state)
  • Pseudo-elements selectors (select and style a part of an element)
  • Attribute selectors (select elements based on an attribute or attribute value)

 

Example

The CSS rule below will be applied to the HTML element with id=”para1″:

#para1 {
text-align: center;
color: red;
}

The CSS Grouping Selector

The grouping selector selects all the HTML elements with the same style definitions.

h1, h2, p {
text-align: center;
color: red;
}

 

The CSS Universal Selector

The universal selector (*) selects all HTML elements on the page.

* {
text-align: center;
color: blue;
}

 

All CSS Simple Selectors

Selector Example Example description
.class .intro Selects all elements with class=”intro”
#id #firstname Selects the element with id=”firstname”
* * Selects all elements
element p Selects all <p> elements
element,element,.. div, p Selects all <div> elements and all <p> elements