CSS3 Selectors and Properties

Last Updated: 22nd June, 2023

Introduction

Imagine that you are designing a website for a clothing store. You want the website to be visually appealing and easy to navigate, so you decide to use CSS3 selectors and properties to style the HTML elements.

First, you use element selectors to target all the <h1> and <h2> tags on the website. You set the font size, color, and weight to create a consistent and visually appealing heading style across the site.

Next, you use class selectors to target specific elements on the site. For example, you create a "featured" class that targets specific products on the homepage. You use CSS3 properties like background color, border, and font size to make the featured products stand out and attract attention.

You also use ID selectors to target specific elements on the site. For example, you use an ID selector to target the navigation bar at the top of the page. You use CSS3 properties like background color, font size, and padding to create a visually appealing and functional navigation bar.

By using CSS3 selectors and properties, you are able to create a visually appealing and easy-to-navigate website for the clothing store. You are able to style specific elements on the site, create a consistent look and feel across the site, and create a functional and visually appealing navigation bar. Without CSS3 selectors and properties, the website would look plain and unappealing, and users would have a harder time navigating the site.

CSS3 Selectors

CSS selectors are a set of patterns that are used to select HTML elements and apply styles to them. Selectors allow developers to target specific elements on a web page and apply styling rules to them, such as setting the color, font-size, or positioning of an element.

There are various types of CSS selectors available, such as tag selectors, class selectors, ID selectors, attribute selectors, and pseudo-selectors. Each selector type has its own syntax and specificity rules, which allow developers to select elements based on their tag name, class, ID, attributes, or relationship with other HTML elements.

CSS selectors play a crucial role in separating the presentation of a web page from its content, making it easier to maintain and update the styling of a site. By using selectors effectively, developers can create visually appealing and responsive websites that meet the needs of users across different devices and platforms.

Syntax of CSS Selectors:

The syntax of a CSS selector consists of a selector and a declaration block. The selector selects one or more HTML elements, while the declaration block contains one or more declarations that define the styles to be applied to the selected elements.

The basic syntax of a CSS selector is as follows:

selector {
  property: value;
}

Selectors can be simple or complex, depending on the level of specificity required. Simple selectors are used to target a single element, while complex selectors are used to target multiple elements or specific combinations of elements.

CSS Selector Types

CSS selectors can be divided into different types based on how they select elements. Here are some of the most commonly used CSS selectors:

Element selectors

Element selectors are the most basic type of selector in CSS. They target all elements of a specific type, such as <p> or <h1>. To use an element selector, simply specify the element name, followed by curly braces that contain the desired styling properties. For example, to target all paragraphs on a page, we would use the following code:

p {
  color: red;
}

Class Selector

Class selectors are used to target specific elements that have been assigned a specific class attribute in the HTML code. Class selectors are identified with a period (.) For example, to target all elements with the class "btn", we would use the following code:

.btn {
  background-color: blue;
}

ID Selector

ID selectors are used to target specific elements that have been assigned a specific ID attribute in the HTML code. ID selectors are identified with a hash (#) followed by the ID name. For example, to target the element with the ID "header", we would use the following code:

#header {
  font-size: 24px;
}

Attribute Selector

Attribute selectors are used to target elements that have specific attributes. Attribute selectors are identified by placing the attribute name inside square brackets. For example, to target all links with the attribute "target=_blank", we would use the following code:

a[target=_blank] {
  color: purple;
}

Pseudo-selectors are used to select elements that are not part of the HTML code, such as the first child, last child, or even odd or even numbered elements. Pseudo-selectors are identified with a colon (:) followed by the desired selector. For example:

li:first-child {
   font-weight: bold;
}

CSS3 Properties

CSS properties allow developers to control various aspects of an element's presentation, such as its size, color, position, and typography.

Each CSS property has a name and a value, which define the specific styling rule to be applied to an HTML element. For example, the "background-color" property can be used to set the background color of an element, and the "font-size" property can be used to set the size of the text within an element.

CSS properties can be applied to HTML elements using CSS selectors. Once a selector has been chosen, CSS properties can be applied to that selector to style the element. CSS properties control the look and feel of the element, including its size, color, position, and more.

CSS properties are specified inside curly braces following the selector. Properties are written in the format "property: value;", with each property-value pair separated by a semicolon (;). For example:

p {
   color: red;
   font-size: 16px;
   margin: 10px;
}

In this example, the color property is set to red, the font-size property is set to 16 pixels, and the margin property is set to 10 pixels.

Some common CSS properties include:

• font-family: sets the font for text within an element.
• color: sets the text color within an element.
• background-color: sets the background color of an element.
• border: sets the border properties of an element.
• margin: sets the margin properties of an element.
• padding: sets the padding properties of an element.
• display: controls how an element is displayed on the page (e.g., block, inline, flex, etc.).
• position: sets the positioning properties of an element (e.g., relative, absolute, fixed, etc.).
• width/height: sets the width and height dimensions of an element.

Conclusion

In conclusion, CSS selectors and properties are essential tools for web developers, enabling them to create visually appealing and responsive websites. CSS selectors provide a powerful and flexible means of selecting and applying styles to HTML elements based on their tag name, class, ID, attributes, or relationship with other elements. On the other hand, CSS properties control the presentation of HTML elements by specifying various aspects, including size, color, position, and typography. By using CSS selectors and properties effectively, developers can create engaging and dynamic web pages that meet the needs of users across different devices and platforms. Therefore, mastering CSS selectors and properties is a crucial skill for any web developer looking to enhance their web development abilities.