css Audio - Active file-generic CSS - Active Generic - Active HTML - Active JS - Active SVG - Active Text - Active file-generic Video - Active header Love html icon-new-collection icon-person icon-team numbered-list123 pop-out spinner split-screen star tv

Pen Settings

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. If you link to another Pen, it will include the CSS from that Pen. If the preprocessor matches, it will attempt to combine them before processing.

+ add another resource

You're using npm packages, so we've auto-selected Babel for you here, which we require to process imports and make it all work. If you need to use a different JavaScript preprocessor, remove the packages in the npm tab.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource

Use npm Packages

We can make npm packages available for you to use in your JavaScript. We use webpack to prepare them and make them available to import. We'll also process your JavaScript with Babel.

⚠️ This feature can only be used by logged in users.

Code Indentation

     

Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

            
              <h1>
  CSS level 4 color blend adjuster just with custom properties and calc()
</h1>

<div>
  <div class="fg">Foreground</div>
  <div class="bg">Background</div>
  <div class="blended">Foreground blended with background by <em>blend percentage</em> in the HSL space</div>
</div>

<form>
  <label><strong>Blend amount</strong></label><input type="range" name="--blend-amount" value="50"/><code></code>
  <label>Background hue</label><input type="range" name="--bg-h" value="180" min="0" max="360"/><code></code>
  <label>Background saturation</label><input type="range" name="--bg-s" value="100"/><code></code>
  <label>Background lightness</label><input type="range" name="--bg-l" value="50"/><code></code>
  <label>Foreground hue</label><input type="range" name="--fg-h" value="240" min="0" max="360"/><code></code>
  <label>Foreground saturation</label><input type="range" name="--fg-s" value="100"/><code></code>
  <label>Foreground lightness</label><input type="range" name="--fg-l" value="50"/><code></code>
</form>
            
          
!
            
              /*
  The CSS level 4 blend adjuster mimicked with just custom properties and calc().
  While it's pretty straightforward to mimick the hue, saturation and
  lightness adjusters, blend requires a bit more math.
  Results might not be 100% in line with the spec, but are very much usable IMHO.
  Syntax of course is even more bloated than for the simple adjusters mentioned above.
*/
body {
  /* Actual values set from JS */
  --bg-h: 0; --bg-s: 0; --bg-l: 0; /* Background hue, saturation, lightness. */
  --fg-h: 0; --fg-s: 0; --fg-l: 0; /* Foreground hue, saturation, lightness. */
  /* The percentage for the blend() adjuster (just unit-less in this case),
     see https://www.w3.org/TR/css-color-4/#modifying-colors */
  --blend-amount: 0;
  
  /* If you see a pink blend result, you might have a syntax error somwehere below this. */
  --blend-result: pink;
  
  /* The result of blending foreground with background in the HSL space by --blend-amount: */
  --blend-result: hsl(
    calc(
      (var(--fg-h) * ((100 - var(--blend-amount)) * 0.01)) +
      (var(--bg-h) * (var(--blend-amount) * 0.01))
    ),
    calc((
      (var(--fg-s) * ((100 - var(--blend-amount)) * 0.01)) +
      (var(--bg-s) * (var(--blend-amount) * 0.01))
    ) * 1%),
    calc((
      (var(--fg-l) * ((100 - var(--blend-amount)) * 0.01)) +
      (var(--bg-l) * (var(--blend-amount) * 0.01))
    ) * 1%)
  );
}

/* A few demo styles. */
h1 {
  /* This is how colors need to be specified.
     Conversion of saturation and lightness to percentage done here to enable prior calculations. */
  background-color: hsl(var(--bg-h), calc(var(--bg-s) * 1%), calc(var(--bg-l) * 1%));
  color: var(--blend-result);

  font-weight: bold;
  font-size: 26px;
  padding: 1em;
  position: relative;
}
body {
  font-family: system, -apple-system, ".SFNSText-Regular", "San Francisco", "Roboto", "Segoe UI", "Helvetica Neue", "Lucida Grande", sans-serif;
}
body > div {
  display: flex;
  flex-wrap: wrap;
  justify-content: left;
  margin: 0 -.5em;
}
div > div {
  color: white;
  text-shadow: 1px 1px 1px black;
  flex: max-content 0 0;
  padding: 3em;
  margin: .5em;
}
/* div + div { margin-left: 2em } */
.bg { background-color: hsl(var(--bg-h), calc(var(--bg-s) * 1%), calc(var(--bg-l) * 1%)) }
.fg { background-color: hsl(var(--fg-h), calc(var(--fg-s) * 1%), calc(var(--fg-l) * 1%)) }
.blended { background-color: var(--blend-result) }
form {
  display: grid;
  grid-template-columns: minmax(min-content, max-content) max-content max-content;
  grid-gap: .5em;
  align-items: center;
  margin-top: 1em;
}
code { text-align: right }
            
          
!
            
              const updateStyle = element => document.body.style.setProperty(element.name, element.value) || (element.nextElementSibling.innerText = element.value)
Array.from(document.querySelectorAll('input')).forEach(input => updateStyle(input))
document.addEventListener('input', ({ target }) => requestAnimationFrame(() => updateStyle(target)))
            
          
!
999px
🕑 One or more of the npm packages you are using needs to be built. You're the first person to ever need it! We're building it right now and your preview will start updating again when it's ready.
Loading ..................

Console