Similar to the contextual text color classes, easily set the background of an element to any contextual class. Background utilities do not set color, so in some cases you'll want to use .text-* utilities.
<div class="bg-primary">.bg-primary</div>
<div class="bg-secondary">.bg-secondary</div>
<div class="bg-success">.bg-success</div>
<div class="bg-danger">.bg-danger</div>
<div class="bg-warning">.bg-warning</div>
<div class="bg-info">.bg-info</div>
<div class="bg-light">.bg-light</div>
<div class="bg-dark">.bg-dark</div>
<div class="bg-white">.bg-white</div>
<div class="bg-transparent">.bg-transparent</div>
Note
Sometimes contextual classes cannot be applied due to the specificity of another selector. In some cases, a sufficient workaround is to wrap your element's content in a <div> with the class.
Conveying meaning to assistive technologies
Using color to add meaning only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (e.g. the visible text), or is included through alternative means, such as additional text hidden with the .sr-only class.