Backgrounds

Background Size

Utilities for controlling the background size of an element’s background image.

Quick reference

Class
Properties
bg-autobackground-size: auto;
bg-coverbackground-size: cover;
bg-containbackground-size: contain;

Basic usage

Auto

Use bg-auto to display the background image at its default size.

Background Size - 图1

  1. <div class="bg-auto bg-no-repeat bg-center ..." style="background-image: url(...)"></div>

Cover

Use bg-cover to scale the background image until it fills the background layer.

Background Size - 图2

  1. <div class="bg-cover bg-center ..." style="background-image: url(...)"></div>

Contain

Use bg-contain to scale the background image to the outer edges without cropping or stretching.

Background Size - 图3

  1. <div class="bg-contain bg-center ..." style="background-image: url(...)"></div>

Applying conditionally

Hover, focus, and other states

Tailwind lets you conditionally apply utility classes in different states using variant modifiers. For example, use hover:bg-contain to only apply the bg-contain utility on hover.

  1. <div class="bg-auto hover:bg-contain">
  2. <!-- ... -->
  3. </div>

For a complete list of all available state modifiers, check out the Hover, Focus, & Other States documentation.

Breakpoints and media queries

You can also use variant modifiers to target media queries like responsive breakpoints, dark mode, prefers-reduced-motion, and more. For example, use md:bg-contain to apply the bg-contain utility at only medium screen sizes and above.

  1. <div class="bg-auto md:bg-contain">
  2. <!-- ... -->
  3. </div>

To learn more, check out the documentation on Responsive Design, Dark Mode and other media query modifiers.


Using custom values

Customizing your theme

By default, Tailwind provides utilities for auto, cover, and contain background sizes. You can change, add, or remove these by editing the theme.backgroundSize section of your config.

tailwind.config.js

  1. module.exports = {
  2. theme: {
  3. backgroundSize: {
  4. 'auto': 'auto',
  5. 'cover': 'cover',
  6. 'contain': 'contain',
  7. '50%': '50%',
  8. '16': '4rem',
  9. }
  10. }
  11. }

Learn more about customizing the default theme in the theme customization documentation.

Arbitrary values

If you need to use a one-off background-size value that doesn’t make sense to include in your theme, use square brackets to generate a property on the fly using any arbitrary value.

  1. <div class="bg-[length:200px_100px]">
  2. <!-- ... -->
  3. </div>

Learn more about arbitrary value support in the arbitrary values documentation.