.icon {
    color: #fff;
    width: 40px;
    height: 40px;
    line-height: 35px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    text-align: center;
    border: 2px solid transparent;
    -webkit-transition: .3s all ease;
    -o-transition: .3s all ease;
    transition: .3s all ease;
}

.icon:hover {
    background: transparent;
    border: 2px solid #fff;
}