humhub/static/resources/user/authChoice.css

.or-container {
    text-align: center;
    margin: 0;
    margin-top:-10px;
    padding: 0;
    clear: both;
    color: #6a737c;
    font-variant: small-caps;
}                    

.or-container hr {
    margin-bottom: 0;
    position: relative;
    top: 19px;
    height: 0;
    border: 0;
    border-top: 1px solid #e4e6e8;
}

.or-container div {
    display: inline-block;
    position: relative;
    padding: 8px;

    background-color: #FFF;
}

.authChoiceMore {
    display:none;
    padding-top:6px;
}

.authChoiceMore a {
    margin-top:6px !important;
} 

.authChoice i {
    padding-right:7px;
}

#btnAuthChoiceMore i {
    padding-right:0px;
}

.auth-clients {
    padding:0px !important;
    margin:0px !important;
}



.btn-fb, .btn-fb:hover, .btn-fb:active, .btn-fb:visited {
    color:white !important;
    background-color: #395697 !important;
}
.btn-steam, .btn-steam:hover, .btn-steam:active, .btn-steam:visited {
    color:white !important;
    background-color: #000 !important;
}   
.btn-github, .btn-github:hover, .btn-github:active, .btn-github:visited {
    color:white !important;
    background-color: #4078C0 !important;
}
.btn-linkedin, .btn-linkedin:hover, .btn-linkedin:active, .btn-linkedin:visited {
    color:white !important;
    background-color: #0077B5 !important;
}
.btn-twitter, .btn-twitter:hover, .btn-twitter:active, .btn-twitter:visited {
    color:white !important;
    background-color: #1da1f2 !important;
}