:before aliagnment

HTML

<ol>
    <li>
        <span>Thickness</span>
    </li>
    <li>
        <span>Size</span>
    </li>
    <li>
        <span>Cart</span>
    </li>
</ol>

CSS

ol {
    color: #000;
    display: block;
    font-family: Arial, Helvetica, Verdana, sans-serif;
    font-size: 12px;
    height: 50px;
    list-style-image: none;
    list-style-position: outside;
    list-style-type: none;
    margin-bottom: 0px;
    margin-left: 0px;
    margin-right: 0px;
    padding-bottom: 0px;
    padding-left: 0px;
    padding-right: 0px;
    padding-top: 0px;
    position: relative;
    width: 960px;
}
li {
    color: #000;
    display: list-item;
    float: left;
    font-family: Arial, Helvetica, Verdana, sans-serif;
    font-size: 12px;
    height: 50px;
    list-style-image: none;
    list-style-position: outside;
    list-style-type: none;
    margin-bottom: 0px;
    margin-left: 0px;
    margin-right: 0px;
    margin-top: 0px;
    padding-bottom: 0px;
    padding-left: 0px;
    padding-right: 0px;
    padding-top: 0px;
    text-align: left;
    width: 190px;
}
span {
    -webkit-transition-delay: 0s;
    -webkit-transition-duration: 1.5s;
    -webkit-transition-property: all;
    -webkit-transition-timing-function: ease-in-out;
    color: #808080;
    display: inline-block;
    font-family: Arial, Helvetica, Verdana, sans-serif;
    font-size: 16px;
    font-style: italic;
    font-weight: bold;
    height: 50px;
    line-height: 47px;
    list-style-image: none;
    list-style-position: outside;
    list-style-type: none;
    margin-bottom: 0px;
    margin-left: 0px;
    margin-right: 0px;
    margin-top: 0px;
    padding-bottom: 0px;
    padding-left: 0px;
    padding-right: 0px;
    padding-top: 0px;
    text-align: center;
    transition-delay: 0s;
    transition-duration: 1.5s;
    transition-property: all;
    transition-timing-function: ease-in-out;
    width: 190px;
}
span:before {
    content: url(https://dl.dropboxusercontent.com/u/6114719/progress-2.png);
    display: inline-block;
    position: relative;
    top: 4px;
    margin-right: 5px;
    transition: all 1.5s ease-in-out;
    -webkit-transition: all 1.5s...