a.btn.fb-login{
    text-align: center;
    font-size: 1em;
    display: inline-block;
    margin: 10px 0;
    padding: 8px 10px;
    color: #fff;
    background-color: #3b5998;
    border: 1px #3b5998 solid;
    transition: all 0.3s ease-in;
    border-radius: 0px;
}
a.btn.fb-login:hover{
    text-decoration: none;
    background-color: #2e4678;    
    border-color: #2e4678;    
}