Chapter 2: Selectors and Properties

In this chapter, we will dive into the core concepts of CSS selectors and properties. We will explore how selectors are used to target specific HTML elements, and how properties are used to modify the appearance and behavior of those targeted elements. By the end of this chapter, you will have a solid understanding of how to use selectors and properties to create visually appealing and responsive websites.

Understanding Selectors

1.1 Introduction to Selectors

Selectors are an essential part of CSS, as they are used to target specific HTML elements. By targeting these elements, we can apply specific styles to them, allowing us to create visually appealing and responsive websites. In this sub-chapter, we will explore the role of selectors in CSS and how they are used to target specific HTML elements.

Summary

Selectors are used to target specific HTML elements in CSS. By targeting these elements, we can apply specific styles to them, allowing us to create visually appealing and responsive websites.

1.2 Element Selectors

Element selectors are the most basic type of selector in CSS. They target HTML elements based on their tag names. For example, if we want to apply a style to all <p> elements on a page, we can use the p element selector.

Example

p {
  color: blue;
}

In this example, we are targeting all <p> elements on the page and setting their color to blue.

Summary

Element selectors target HTML elements based on their tag names. By using element selectors, we can apply styles to all instances of a particular HTML element on a page.

1.3 Class Selectors

Class selectors are used to target HTML elements based on their class attributes. A class is a name that is assigned to an HTML element using the class attribute. Class selectors are denoted by a period (.) followed by the name of the class.

Example

<p class="highlight">This is a highlighted paragraph.</p>

.highlight {
  background-color: yellow;
}

In this example, we have assigned the highlight class to a <p> element. We then use a class selector to target all elements with the highlight class and set their background color to yellow.

Summary

Class selectors are used to target HTML elements based on their class attributes. By using class selectors, we can apply styles to specific instances of an HTML element on a page.

1.4 ID Selectors

ID selectors are similar to class selectors, but they are used to target HTML elements based on their unique ID attributes. An ID is a name that is assigned to an HTML element using the id attribute. ID selectors are denoted by a pound sign (#) followed by the name of the ID.

Example

<h1 id="main-heading">Welcome to My Website</h1>

#main-heading {
  text-align: center;
}

In this example, we have assigned the main-heading ID to an <h1> element. We then use an ID selector to target the element with the main-heading ID and center-align its text.

Summary

ID selectors are used to target HTML elements based on their unique ID attributes. By using ID selectors, we can apply styles to specific instances of an HTML element on a page.

1.5 Attribute Selectors

Attribute selectors are used to target HTML elements based on specific attribute values or types. They are denoted by square brackets ([]) followed by the name of the attribute and its value.

Example

<input type="text" name="username" required>

input[required] {
  border: 2px solid red;
}

In this example, we are targeting all <input> elements with the required attribute and setting their border to 2px solid red.

Summary

Attribute selectors are used to target HTML elements based on specific attribute values or types. By using attribute selectors, we can apply styles to elements based on their attributes.

1.6 Pseudo-classes

Pseudo-classes are used to target HTML elements based on their state or user interaction. They are denoted by a colon (:) followed by the name of the pseudo-class.

Example

<a href="https://www.example.com">Visit Example</a>

a:hover {
  text-decoration: underline;
}

In this example, we are targeting all <a> elements when the user hovers over them and underlining their text.

Summary

Pseudo-classes are used to target HTML elements based on their state or user interaction. By using pseudo-classes, we can apply styles to elements based on their behavior.

Working with Properties

2.1 Introduction to Properties

Properties are used to modify the appearance and behavior of targeted HTML elements. In this sub-chapter, we will explore the role of properties in CSS and how they are used to modify the appearance and behavior of targeted HTML elements.

Summary

Properties are used to modify the appearance and behavior of targeted HTML elements. By using properties, we can create visually appealing and responsive websites.

2.2 Cascading and Inheritance

Cascading and inheritance are two important concepts in CSS. Cascading refers to the way that multiple CSS rules are applied to the same HTML element. Inheritance refers to the way that styles are passed down from parent elements to child elements.

Example

<body>
  <p>This is a paragraph.</p>
</body>

body {
  font-family: Arial;
}

p {
  color: blue;
}

In this example, we have set the font family of the <body> element to Arial. We have also set the color of the <p> element to blue. Since the <p> element is a child of the <body> element, it inherits the font family style from its parent.

Summary

Cascading and inheritance are two important concepts in CSS. Cascading refers to the way that multiple CSS rules are applied to the same HTML element, while inheritance refers to the way that styles are passed down from parent elements to child elements.

2.3 Box Model and Layout Properties

The box model is a fundamental concept in CSS layout. It defines the way that HTML elements are laid out on a page. Layout properties are used to control the positioning and arrangement of HTML elements.

Example

<div class="box"></div>

.box {
  width: 200px;
  height: 200px;
  border: 1px solid black;
  margin: 10px;
  padding: 20px;
  box-sizing: border-box;
  float: left;
}

In this example, we have created a <div> element with a class of box. We have set its width and height to 200px, and added a border, margin, and padding. We have also set the box-sizing property to border-box, which includes the border and padding in the total width and height of the element. Finally, we have used the float property to arrange the element side-by-side with other elements.

Summary

The box model is a fundamental concept in CSS layout. Layout properties are used to control the positioning and arrangement of HTML elements.

2.4 Text Properties

Text properties are used to control the appearance of text within HTML elements. They include properties such as color, font-family, font-size, and text-align.

Example

<p>This is a paragraph with some text.</p>

p {
  color: red;
  font-family: Times New Roman;
  font-size: 24px;
  text-align: center;
}

In this example, we have set the color of the <p> element to red, the font family to Times New Roman, the font size to 24px, and the text alignment to center.

Summary

Text properties are used to control the appearance of text within HTML elements. They include properties such as color, font-family, font-size, and text-align.

2.5 Background Properties

Background properties are used to set background colors, images, and repeats for HTML elements. They include properties such as background-color, background-image, and background-repeat.

Example

<div class="box"></div>

.box {
  width: 200px;
  height: 200px;
  background-color: lightblue;
  background-image: url("image.jpg");
  background-repeat: no-repeat;
}

In this example, we have created a <div> element with a class of box. We have set its background color to light blue, added a background image, and set the background repeat to no-repeat.

Summary

Background properties are used to set background colors, images, and repeats for HTML elements. They include properties such as background-color, background-image, and background-repeat.

2.6 Border and Margin Properties

Border and margin properties are used to add spacing and define edges around HTML elements. They include properties such as border, border-width, border-style, margin, and padding.

Example

<p>This is a paragraph with some text.</p>

p {
  border: 1px solid black;
  border-width: 2px;
  border-style: dashed;
  margin: 10px;
  padding: 20px;
}

In this example, we have added a border to the <p> element with a width of 2px and a dashed style. We have also added a margin of 10px and padding of 20px.

Summary

Border and margin properties are used to add spacing and define edges around HTML elements. They include properties such as border, border-width, border-style, margin, and padding.