.block-social li.twitter a:before {
    content: "";
    background: url("data:image/png;base64,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") no-repeat;
    width: 15px;
    height: 15px;
    display: inline-block;
    vertical-align: middle;
    background-position: center;
    background-size: 15px 15px;
}

.block-social li.twitter a:hover:before {
    background: url("data:image/png;base64,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") no-repeat;
    background-position: center;
    background-size: 15px 15px;
}
