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HTML 

              
                <p>Negative/defensive use of <code>prefers-reduced-motion</code>: only run animations in browsers that <em>do</em> support the media feature - and there, only if they have <em>not</em> expressed a preference for reduced motion, i.e. <code>(prefers-reduced-motion:no-preference)</code> evaluates to true. In older browsers (such as IE11) where users can't signal their preference, simply don't animate.</p>

<div class="animation">animated box</div>

<pre><code>@media (prefers-reduced-motion: no-preference) {
  .animation {
    animation: vibrate 0.3s linear infinite both; 
  }
}</code></pre>

<p>To clarify, this is the exact opposite of most current approaches, where an animation is defined, and then suppressed if <code>(prefers-reduced-motion:reduce)</code> evaluates to true.</p>

<pre><code>.animation {
  animation: vibrate 0.3s linear infinite both; 
}

@media (prefers-reduced-motion: reduce) {
  .animation {
    animation: none;
  }
}</code></pre>

<p>The issue with that approach is that in browsers that <em>don't</em> support the <code>prefers-reduced-motion</code> media feature, there's no way for users to then turn animations off. Instead, with the defensive approach, in these cases animations won't run either.</p>

<p>Based on <a href="https://twitter.com/derSchepp/status/1202223608719908865" target="_blank">this idea by Christian Schaefer</a>. Example code/CSS from <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/@media/prefers-reduced-motion" target="_blank">MDN's <code>prefers-reduced-motion</code> reference</a>.</p>
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CSS 

              
                /* only run animation explicitly in browsers that support prefers-reduced-motion itself. old browsers (IE11 etc) won't get any animation. */

@media (prefers-reduced-motion: no-preference) {
  .animation {
    animation: vibrate 0.3s linear infinite both; 
  }
}


.animation {
  background-color: rebeccapurple;
  color: #fff;
  font: 1.2em Helvetica, arial, sans-serif;
  width: 200px;
  padding: 1em;
  border-radius: 1em;
  text-align: center;  
}

/* ----------------------------------------------
 * Generated by Animista on 2018-9-2 13:47:0
 * w: http://animista.net, t: @cssanimista
 * ---------------------------------------------- */

/**
 * ----------------------------------------
 * animation vibrate-1
 * ----------------------------------------
 */

@keyframes vibrate {
  0% {
            transform: translate(0);
  }
  20% {
            transform: translate(-2px, 2px);
  }
  40% {
            transform: translate(-2px, -2px);
  }
  60% {
            transform: translate(2px, 2px);
  }
  80% {
            transform: translate(2px, -2px);
  }
  100% {
            transform: translate(0);
  }
}

/* some generic styles for the demo explanation itself */

p code, pre { background: #f5f5f5; border: #ddd solid 1px; }
p code { padding: 0 0.25em; margin: 0 0.15em; }
pre { padding: 1em 1.5em; }
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JS
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