What are the 4 CSS rules?

Cascading Style Sheets (CSS) are essential in web design for controlling the visual appearance of a website. There are four main CSS rules: Selector, Property, Value, and Declaration.

The Selector determines which elements on a webpage will be affected by the CSS rules. The Property specifies the aspect of the selected element that will be altered. The Value defines the specific change to be applied, such as color or size. Finally, the Declaration consists of the property and value pair enclosed within curly brackets.

Cascading Style Sheets (CSS)

CSS, which stands for Cascading Style Sheets, is a programming language used to control the presentation and layout of HTML elements on a web page. By applying CSS rules, developers can modify the appearance of a website, including colors, fonts, spacing, and more. CSS allows for the separation of content and design, making it easier to maintain and update websites.

The Basic CSS Syntax

Before diving into the 4 CSS rules, it’s important to understand the basic syntax of CSS. CSS rules consist of a selector and a declaration block. The selector specifies which HTML element(s) the rule should apply to, and the declaration block contains the properties and values that define the styling of those elements.

Here’s an example of the basic CSS syntax:

selector {
    property: value;
    property: value;
    ...
}

In the example above, “selector” represents the HTML element(s) targeted by the rule, “property” is the CSS property being modified, and “value” is the desired value for that property. Multiple properties can be declared within the same rule, separated by semicolons.

The 4 CSS Rules Explained

1. Selector

The selector determines which HTML element(s) the CSS rule applies to. There are various types of selectors available in CSS:

a) Tag Selectors

Tag selectors target specific HTML tags. For example, to apply a rule to all p tags, the following selector would be used:

p {
    property: value;
    ...
}

b) Class Selectors

Class selectors are used to target elements with a specific class attribute. To apply a rule to all elements with the class “example,” the selector would look like this:

.example {
    property: value;
    ...
}

c) ID Selectors

ID selectors target a single element with a specific ID attribute. To apply a rule to an element with the ID “header,” the selector would be written as follows:

#header {
    property: value;
    ...
}

d) Attribute Selectors

Attribute selectors match elements based on their attribute values. For example, to target all a tags with a “target” attribute, the selector would be:

a[target] {
    property: value;
    ...
}

e) Pseudo-classes and Pseudo-elements

Pseudo-classes and pseudo-elements target elements based on their state or position. An example of a pseudo-class selector targeting a hovered link is:

a:hover {
    property: value;
    ...
}

2. Property

The property determines which aspect of the targeted element(s) will be modified. CSS provides a wide range of properties for manipulating elements, such as:

• color: Specifies the text color
• background-color: Sets the background color
• font-size: Defines the size of the text
• margin: Controls the spacing around an element
• padding: Sets the spacing between the content and the border
• border: Configures the border properties
• And many more…

Each property takes a specific value, such as a color code, length measurement, or a predefined keyword, to determine the desired effect on the element.

3. Value

The value defines the specific modification to be made to the targeted element(s), based on the chosen property. For example, if the property “color” is set to “red,” the text color of the targeted element(s) will turn red.

Values can be numerical, textual, or even functions. They are unique to each property and determine the appearance or behavior of the selected element(s).

4. Declaration

A declaration consists of a property-value pair and ends with a semicolon. It is written within the declaration block of a CSS rule to define the styling for the selected element(s). Multiple declarations can be included within a rule, each separated by a semicolon.

Here’s an example of multiple declarations within a rule:

selector {
    property1: value1;
    property2: value2;
    ...
}

Declarations allow developers to customize the appearance of web pages according to their specific design requirements.

Understanding the 4 CSS rules is essential for efficiently styling web pages. The selector determines which element(s) the rule applies to, the property determines what aspect of the element will be changed, the value specifies the modification, and the declaration block contains one or more declarations. By mastering these fundamental concepts of CSS, developers can create visually appealing and user-friendly websites.

The four essential CSS rules are selector, property, value, and declaration. These rules are fundamental in styling and formatting web pages to create visually appealing and functional websites. Mastering these rules is key to successfully using CSS for web design.