.clearfix:before,
.clearfix:after {
    content: " ";
    display: table;
}

.clearfix:after {
    clear: both;
}

.clearfix {
    *zoom: 1;
}

.center {
    margin-left: auto;
    margin-right: auto;
}

.bold {
    font-weight: bold;
}

.btn:focus {
    outline: none;
}