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Responsive Container Aspect Ratio CSS

Beginner

This tutorial is from open-source community. Access the source code

Introduction

In this lab, we will learn how to create a responsive container with a specified aspect ratio using CSS. You will be introduced to the --aspect-ratio custom property and how to use the calc() function to calculate the container's height. You will also learn how to set the child element to maintain the aspect ratio using the object-fit: cover property. By the end of this lab, you will have a better understanding of how to create visually appealing and responsive containers on your web pages.

This is a Guided Lab, which provides step-by-step instructions to help you learn and practice. Follow the instructions carefully to complete each step and gain hands-on experience. Historical data shows that this is a beginner level lab with a 96% completion rate. It has received a 100% positive review rate from learners.

Aspect Ratio

index.html and style.css have already been provided in the VM.

This code creates a responsive container with a specific aspect ratio using CSS custom properties and calc() function. Follow these steps to achieve this:

  1. Define the desired aspect ratio using a CSS custom property, --aspect-ratio.
  2. Set the container element's position property to relative and its height property to 0.
  3. Calculate the container element's height using the calc() function and the --aspect-ratio custom property, and set it as the padding-bottom property.
  4. Set the direct child of the container element to position: absolute, top: 0, left: 0, width: 100%, and height: 100%.
  5. Maintain the aspect ratio of the child element by setting its object-fit property to cover.

Use the following HTML and CSS code to create the container:

<div class="container">
  <img src="https://picsum.photos/id/119/800/450" />
</div>

.container {
  --aspect-ratio: 16/9;
  position: relative;
  height: 0;
  padding-bottom: calc(100% / var(--aspect-ratio));
}

.container > * {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

Please click on 'Go Live' in the bottom right corner to run the web service on port 8080. Then, you can refresh the Web 8080 Tab to preview the web page.

Summary

Congratulations! You have completed the Aspect Ratio lab. You can practice more labs in LabEx to improve your skills.