CSS Variable Fun

You heard it here first

by Ford Heacock

HTML

<h2>Update CSS Variables with <span class='hl'>JS</span></h2>

  <div class="controls">
    <label for="spacing">Spacing:</label>
    <input id="spacing" type="range" name="spacing" min="10" max="200" value="10" data-sizing="px">

    <label for="blur">Blur:</label>
    <input id="blur" type="range" name="blur" min="0" max="25" value="10" data-sizing="px">

    <label for="base">Base Color</label>
    <input id="base" type="color" name="base" value="#ffc600">
  </div>

  <img src="https://source.unsplash.com/7bwQXzbF6KE/800x500">

CSS

:root {
        --base: #ffc600;
        --spacing: 10px;
        --blur: 10px;
    }

    img {
        padding: var(--spacing);
        background: var(--base);
        filter: blur(var(--blur));
    }

    .h1 {
        color: var(--base);
    }
    /*
      misc styles, nothing to do with CSS variables
    */

    body {
      text-align: center;
    }

    body {
      background: #193549;
      color: white;
      font-family: 'helvetica neue', sans-serif;
      font-weight: 100;
      font-size: 50px;
    }

    .controls {
      margin-bottom: 50px;
    }

    input {
      width:100px;
    }

JavaScript

const inputs = document.querySelectorAll('.controls input');

      function handleUpdate() {
          const suffix = this.dataset.sizing || '';
          document.documentElement.style.setProperty(`--${this.name}`, this.value + suffix);
      }

      inputs.forEach(input => input.addEventListener('change', handleUpdate));
      inputs.forEach(input => input.addEventListener('mousemove', handleUpdate));