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<span class="ss-cart default">Add to cart</span>
<span class="ss-cart">Add to cart</span>

span {
    font-size: 22px;
    font-family: Helvetica, sans-serif;
    color: #aaaaaa;
    margin-right: 20px;
}

.ss-cart:before { 
    font-size: .8em;
    color: #db586f;
    margin-right: 7px;
}

.default:before {
    font-size: 1em;
}