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HTML

              
                <main>
  <div class="article">
    <h1>Cascade Layers.</h1>
    <p>In this example, I'm showcasing the power of <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/@layer">cascade layers</a>, using <code>@layer</code>. This is a <a href="#">link without class name</a>. You can see it appears green. This is a <a href="#" class="link"> link with class of <code>link</code></a>. It, too, appears green, even though I specify the color of <code>.link</code> elements to be blue. While <code>.link</code> has a higher element-level specificity than <code>a</code>, I am setting a color style on <code>a</code> in a higher-precedence <code>@layer</code>.</p>
    <div class="callout">
      <p>The <em>layer</em> precedence beats the <em>element specificity</em>.</p>
    </div>
    <p>Now, I have an even <em>more</em> specific layer called <code>utilities</code> where I have a class called <code>pink</code>. This is a <a href="#" class="pink">link with class of <code>pink</code></a>. This specificity wins.</p>
    <p>Here's what the code looks like (editable). Try removing the <code>typography</code> layer, or adjusting the order of the layers to see what happens:</p>
    <style contenteditable>
@layer base {
  a {
    font-weight: 800;
    color: red; /* ignored */
  }

  .link {
    color: blue; /* ignored */
  }
}

@layer typography {
  a {
    color: green; /* styles *all* links */
  }
}

@layer utilities {
  .pink {
    color: hotpink;  /* styles *all* .pink's */
  }
}
</style>
    <div class="callout"><p>If you reverse the layer order at the top of the file (i.e. the first time the name of the layer is introduced), you'll see a different result. <code>@layer utilities, typography, base;</code> will make the links appear red and blue.</p></div>
  </div>
</main>
              
            
!

CSS

              
                /* Layer style code is editable in the body */

body {
  font-family: system-ui, serif;
  font-size: 20px;
  line-height: 1.8;
  max-width: 700px;
  margin: 0 auto;
  display: grid;
  height: 100vh;
  place-items: center;
}

code {
  background-color: gold;
  padding: 0.25rem;
}

.article {
  background-color: aliceblue;
  padding: 3rem;
}

.callout {
  padding-left: 2rem;
  margin-left: 2rem;
  font-size: 1.5rem;
  border-left: 4px solid hotpink;
}

style {
  display: block;
  background: white;
  border: 1px solid deepskyblue;
  padding: 1rem 2rem;
  line-height: 1.25;
  font-family: monospace;
  white-space: pre-wrap;
  font-size: 1rem;
}

              
            
!

JS

              
                
              
            
!
999px

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