oklch() function is not recognized

[scalisi]

I tried to validate the following CSS (copied from here), which includes the oklch() function:

div {
  width: 100px;
  height: 100px;
  background-color: red;
  color: red;
  background-color: oklch(from currentColor l c h);
}

I received the following error:

Value Error : background-color oklch(from currentColor l c h) is not a background-color value : oklch(from currentColor l c h)

vnu has the same issue.