is there any way to format the captcha pop up?

I want to change the font and colors of the catpcha request pop up. Is there any way to do that? I tried moving the icon a bit and it doesn’t seem to be working. Here are the 2 codes I tried:

.modal-icon {
    margin-top: 20px;
    left: 20px;
    font-family: "FFUnitStdLight", Helvetica, Arial, Verdana, sans-serif;
}
.w3eden .modal-icon {
    margin-top: 20px;
    left: 20px;
    font-family: "FFUnitStdLight", Helvetica, Arial, Verdana, sans-serif;
}