Day 64: the revert-layer keyword

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It’s time to get me up to speed with modern CSS. There’s so much new in CSS that I know too little about. To change that I’ve started #100DaysOfMoreOrLessModernCSS. Why more or less modern CSS? Because some topics will be about cutting-edge features, while other stuff has been around for quite a while already, but I just have little to no experience with it.

With cascade layers comes a new CSS-wide property value, revert-layer.

You can use the revert-layer keyword to roll back the cascade to a value defined in a previous layer.

In the following example, the base layer defines a black color for the border. The theme layer sets the border color to fuchsia. In a print media query within the theme layer we revert the style back to the color in the base layer.

@layer base {
  h2 {
    --border-color: #000;

    border: 4px solid var(--border-color);
  }
}

@layer theme {
  h2 {
    --border-color: fuchsia;
  }

  @media print {
    h2 {
     --border-color: revert-layer;
    }
  }
}
<h2>Sretan Božić!</h2>

Sretan Božić!

If you try to print this page, you will see that the border-color of the <h2> is #000.

See on CodePen

Further reading

Overview: 100 Days Of More Or Less Modern CSS