CSS initial value is used to reset a css property to its user-agent value. It can be used during debugging (e.g. In Chrome developer tools) or to reset a property to its initial value in some third party library.
Here is sample code using css initial
<style type="text/css">
h2 {
color:green;
}
.box > h2 {color:initial};
</style>
<h2>h2 text</h2>
<div class="box">
<h2>h2 text with color initial</h2>
</div>Specification and Browser compatibility
| Specification | Status | Categories |
|---|---|---|
| CSS initial value | W3C Candidate Recommendation | CSS |
| Chrome | Firefox | IE | Edge | Safari | Opera |
|---|---|---|---|---|---|
| Yes 4+ | Yes 19+ | No | Yes 12+ | Yes 3.2+ | Yes 15+ |
| Android Chrome | Android Firefox | iOS Safari | IE Mobile | Opera Mobile |
|---|---|---|---|---|
| Yes 47+ | Yes 44+ | Yes 4.0-4.1+ | No | Yes 33+ |
source: caniuse.com