Chapter 8: Building Navigation Menus

CSS Flexbox is a powerful layout model designed to help you create flexible and responsive layouts. It simplifies the alignment of items within a container, making it easier to adjust layouts across different screen sizes. In this chapter, we’ll explore how to use Flexbox properties to create layouts that adapt seamlessly to various devices.

Setting Up a Flex Container

To start using Flexbox, you need to define a container as a flex container. This is done by setting display: flex; on the container element, allowing all direct children to become flexible items.

/* Setting up a flex container */
.container {
    display: flex;
    flex-direction: row; /* Arrange items in a row */
}

Aligning Items with Justify Content and Align Items

Flexbox allows you to align items horizontally and vertically within the container. Use justify-content for horizontal alignment and align-items for vertical alignment.

/* Horizontal and vertical alignment */
.container {
    display: flex;
    justify-content: space-between; /* Distribute items with space between them */
    align-items: center; /* Align items vertically to the center */
}

Controlling Flex Item Growth, Shrinkage, and Basis

You can control the flexibility of items within a flex container using flex-grow, flex-shrink, and flex-basis. These properties help you adjust the size of items based on the available space in the container.

/* Controlling item size and growth */
.item {
    flex-grow: 1; /* Allow item to grow if needed */
    flex-shrink: 1; /* Allow item to shrink if needed */
    flex-basis: 100px; /* Initial size of item */
}

Creating Responsive Layouts with Flexbox

Flexbox is ideal for creating responsive designs. You can adjust the direction, alignment, and size of items based on screen size, making layouts that look good on both mobile and desktop devices.

/* Responsive Flexbox Layout */
.container {
    display: flex;
    flex-wrap: wrap; /* Wrap items to the next row if needed */
}

.item {
    flex: 1 1 200px; /* Flex-grow, flex-shrink, flex-basis */
    margin: 10px;
}

Example: Building a Responsive Navigation Bar with Flexbox

Let’s create a simple responsive navigation bar using Flexbox. The items will align horizontally on larger screens and stack vertically on smaller screens.

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Responsive Navbar Example</title>
        <link rel="stylesheet" href="styles.css">
    </head>
    <body>
        <nav class="navbar">
            <a href="#">Home</a>
            <a href="#">About</a>
            <a href="#">Services</a>
            <a href="#">Contact</a>
        </nav>
    </body>
</html>

Experimenting with Flexbox

Now that you understand the basics of Flexbox, try experimenting with different alignment options, flex properties, and responsive designs. Flexbox is a versatile tool that makes it easier to build layouts that look great on any device.