CSS selectors for radio buttons previous to one checked
<p>I am building a little star CSS rating via some radio buttons and have it working ok. I am having an issue being able to fill in the stars before the radio selected, so if star 3 is selected, star 1 and 2 would also be filled in. Here is what I have so far: </p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-css lang-css prettyprint-override"><code>#review-form input,
#review-form textarea {
  background: none repeat scroll 0 0 #333333;
  border: 0 none;
  color: #fff;
  margin: 0;
  max-width: 100%;
  padding: 7px 4px;
}
#review-form .radio {
  display: inline-block;
}
#review-form input[type=radio] {
  display: none;
}
#review-form input[type=radio] + label {
  display: block;
}
#review-form input[type='radio'] + label:before {
  display: inline-block;
  font-family: FontAwesome;
  font-style: normal;
  font-weight: normal;
  line-height: 1;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  padding-right: 8px;
  width: 23px;
}
#review-form input[type=radio] + label:before {
  content: "\f006";  /* Radio Unchecked */
}
#review-form input[type=radio]:checked + label:before {
  content: "\f005";  /* Radio Checked */
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link href="//netdna.bootstrapcdn.com/font-awesome/3.0/css/font-awesome.css" rel="stylesheet" /&gt;
&lt;div class="form-group" id="review-form"&gt;
  &lt;label for="rating"&gt;RATING&lt;/label&gt;
  &lt;span class="star-rating star-5"&gt;
                  &lt;div class="radio"&gt;
                    &lt;input type="radio" id="option1" name="star-radios" value="1"&gt;
                    &lt;label for="option1"&gt;&lt;/label&gt;
                  &lt;/div&gt;
                  &lt;div class="radio"&gt;
                    &lt;input type="radio" id="option2" name="star-radios" value="2"&gt;
                    &lt;label for="option2"&gt;&lt;/label&gt;
                  &lt;/div&gt;
                  &lt;div class="radio"&gt;
                    &lt;input type="radio" id="option3" name="star-radios" value="3"&gt;
                    &lt;label for="option3"&gt;&lt;/label&gt;
                  &lt;/div&gt;
                  &lt;div class="radio"&gt;
                    &lt;input type="radio" id="option4" name="star-radios" value="4"&gt;
                    &lt;label for="option4"&gt;&lt;/label&gt;
                  &lt;/div&gt;
                  &lt;div class="radio"&gt;
                    &lt;input type="radio" id="option5" name="star-radios" value="5"&gt;
                    &lt;label for="option5"&gt;&lt;/label&gt;
                  &lt;/div&gt;

                &lt;/span&gt;

&lt;/div&gt;</code></pre>
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<p><strong><a href="http://codepen.io/ajmajma/pen/VmjpQq" rel="nofollow noreferrer">Codepen</a></strong></p>

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<p>I am wondering if there is a CSS selector (or something) available where I can make the change the stars previous to the select radio button. Trying to avoid using JS if I can.</p>