<h2>Update CSS Variables with <span class='hl'>JS</span></h2>
<div class="controls">
  <label>Spacing:</label>
  <input type="range" id="spacing" min="10" max="200" value="10">

  <label>Blur:</label>
  <input type="range" id="blur" min="0" max="25" value="10">

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

<img src="http://unsplash.it/800/500?image=899">

<p class="love">Made by <a href="https://twitter.com/wesbos">@wesbos</a> 😘</p>

<p class="love">Chrome 49+, Firefox 31+</p>

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

body {
  text-align: center;
}

img {
  padding: var(--spacing);
  background: var(--base);
  -webkit-filter: blur(var(--blur));
  /* 👴 */
  filter: blur(var(--blur));
}

.hl {
  color: var(--base);
}

/*
        misc styles, nothing to do with CSS variables
      */

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

.controls {
  margin-bottom: 50px;
}

a {
  color: var(--base);
  text-decoration: none;
}

input {
  width:100px;
}

      // get the inputs
      const inputs = [].slice.call(document.querySelectorAll('.controls input'));

      // listen for changes
      inputs.forEach(input => input.addEventListener('change', handleUpdate));
      inputs.forEach(input => input.addEventListener('mousemove', handleUpdate));

      function handleUpdate(e) {
        // append 'px' to the end of spacing and blur variables
        const suffix = (this.id === 'base' ? '' : 'px');
        document.documentElement.style.setProperty(`--${this.id}`, this.value + suffix);
      }