CSS isolation

<!DOCTYPE html>
<title>Example</title>
<style>
body {
  font-family: sans-serif;
  background-image: url('/pix/samples/15l.jpg');
  background-size: cover;
}
h1 {
  width: 200px;
  padding: 10px;
  float: left;
  background-color: orange;
  color: white;
  mix-blend-mode: overlay;
}
.isolated {
  isolation: isolate;
}
</style>

<div>
  <h1>Not Isolated</h1>
</div>

<div class="isolated">
  <h1>Isolated</h1>
</div>

The CSS isolation property defines whether or not an element will be turned into a new stacking context.

It can be used to isolate an element when it belongs to a group that's blended with its backdrop. By setting the element to isolation: isolate, it won't be blended with its backdrop.

This can be useful if an element inherits blending from the mix-blend-mode property, but you don't want that blending applied to the element.

Syntax

Possible Values

Here are the possible values:

auto: Default value. No isolation is applied to the element, unless otherwise specified within the CSS.
isolate: Creates a new stacking context — isolates the element.

In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:

initial: Represents the value specified as the property's initial value.
inherit: Represents the computed value of the property on the element's parent.
unset: This value acts as either inherit or initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.

Basic Property Information

Initial Value: auto
Applies To: All elements. When used with Scalable Vector Graphics (SVG), it applies to container elements, graphics elements and graphics referencing elements.
Inherited?: No
Media: Visual
Animatable: No

Example Code

Basic CSS

Working Example within an HTML Document

Try it

CSS Specifications

The isolation property is defined in Compositing and Blending Level 1 (W3C Candidate Recommendation, 13 January 2015).

Vendor Prefixes

For maximum browser compatibility many web developers add browser-specific properties by using extensions such as -webkit- for Safari, Google Chrome, and Opera (newer versions), -ms- for Internet Explorer, -moz- for Firefox, -o- for older versions of Opera etc. As with any CSS property, if a browser doesn't support a proprietary extension, it will simply ignore it.

This practice is not recommended by the W3C, however in many cases, the only way you can test a property is to include the CSS extension that is compatible with your browser.

The major browser manufacturers generally strive to adhere to the W3C specifications, and when they support a non-prefixed property, they typically remove the prefixed version. Also, W3C advises vendors to remove their prefixes for properties that reach Candidate Recommendation status.

Many developers use Autoprefixer, which is a postprocessor for CSS. Autoprefixer automatically adds vendor prefixes to your CSS so that you don't need to. It also removes old, unnecessary prefixes from your CSS.

You can also use Autoprefixer with preprocessors such as Less and Sass.

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