<div>
  <input type="radio" id="radio01" name="radio" />
  <label for="radio01"><span></span>Radio Button 1</label>
</div>

<div>
 <input type="radio" id="radio02" name="radio" />
 <label for="radio02"><span></span>Radio Button 2</label>
</div>
$DarkBrown: #292321;
$Orange: #CC3300;

div {
  margin:0 0 0.75em 0;
}

input[type="radio"] {
    display:none;
}
input[type="radio"] + label {
    color: $DarkBrown;
    font-family:Arial, sans-serif;
    font-size:14px;
}
input[type="radio"] + label span {
    display:inline-block;
    width:19px;
    height:19px;
    margin:-1px 4px 0 0;
    vertical-align:middle;
    cursor:pointer;
    border-radius:  50%;
}

input[type="radio"] + label span {
     background-color:$DarkBrown;
}

input[type="radio"]:checked + label span{
     background-color:$Orange;
}

input[type="radio"] + label span,
input[type="radio"]:checked + label span {
  transition:background-color 0.4s linear;
}

External CSS

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External JavaScript

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