CSS Flexbox sets the height of internal elements to 0

In this article, we will introduce CSS Flexbox how to set the height of internal elements to 0, and provide examples.

Flexbox is a CSS module for creating flexible layouts. It allows us to arrange and align elements by defining the relationship between a container and its contents. In some cases, we may wish to set the height of an inner element to zero to achieve special effects, such as creating a container that is stretched by its content.

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Understanding Flexbox Basics

Before setting the height of inner elements to 0, we need to understand some basic Flexbox concepts.

1. Flex container: An element set to display: flex or display: inline-flex. It is the container in Flexbox and is used to contain flex items.

2. Flex element: A direct child element of a flex container. Each flex item is arranged and aligned according to the container’s main and cross axes.

3. Main and cross axes: The main axis is the direction of the flex container, which can be horizontal (row) or vertical (column), with horizontal being the default. The cross axis is perpendicular to the main axis.

4. Flex item: Each flex item in a flex container is a flex item. Each flex item has properties that control its layout within the container.

Setting the height of an inner element to 0

To set the height of an inner element to 0, we use the flex item’s flex property. This property defines how much the flex item expands and contracts within the container. When the flex property is set to 0, the flex item’s dimensions are ignored, and its height becomes 0.

Here’s an example showing how to use Flexbox to set an inner element’s height to 0:

<div class="container">
<div class="item">Item 1</div>
<div class="item">Item 2</div>
<div class="item">Item 3</div>
</div>

.container {
display: flex;
height: 200px;
}

.item {
flex: 0;
background-color: gray;
border: 1px solid black;
padding: 10px;
}

In the example above, we create a flex container and give it a fixed height of 200px. We then set flex: 0 to the flex items, which sets their height to 0. Finally, we add some styles to the flex items for better display.

Automatically Adjusting the Height of Inner Elements

Sometimes, we may want the height of an inner element to automatically adjust based on its content, rather than setting it to zero. To achieve this, we can use the align-items property.

The align-items property determines the alignment of flex items on the cross axis. When set to stretch, the flex item will stretch to fill the height of its container.

Here’s an example showing how to use align-items: stretch to automatically adjust the height of inner elements:

.container {
display: flex;
height: 200px;
align-items: stretch;
}

.item {
background-color: gray;
border: 1px solid black;
padding: 10px;
}

In the example above, we set the align-items property to stretch, which causes the flex items to stretch on the cross axis to fill the height of the container. This way, regardless of the height of the flex item’s content, they will automatically adjust to the same height as the container.

Summary

This article introduced how to use CSS Flexbox to set the height of internal elements to zero, and provided examples. We also learned the basic concepts of flex containers, flex elements, and flex items, and used the flex and align-items properties to achieve specific effects. We hope this article has been helpful in understanding and using CSS Flexbox. For more in-depth knowledge of Flexbox, please refer to the relevant documentation and tutorials.