.mce-i-bctt-tweet {
    font-family: "dashicons";
}

.mce-i-bctt-tweet:before {
    display: inline-block;
    -webkit-font-smoothing: antialiased;
    text-align: center;
    font-weight: 400;
    font-size: 20px;
    line-height: 1;
    font-family: "dashicons";
    content: "\f301";
    color: #4099ff;
    speak: none;
    vertical-align: top;
    position: relative;
}