.hidden{
    display: none;
}

.loading {
    position: fixed;
    top: 0; 
    right: 0;
    bottom: 0; 
    left: 0;
    background: transparent;
}

.loader {
    left: 0px;
    bottom: 0px;
    margin-left: -4em;
    font-size: 10px;
    border: .8em solid transparent;
    border-left: .8em solid rgb(196, 196, 196);
    animation: spin 0.25s infinite linear;
}
.loader, .loader:after {
    border-radius: 50%;
    width: 4em;
    height: 4em;
    display: block;
    position: absolute;
    margin: 1em;
}

@keyframes spin {
    0% {
        transform: rotate(360deg);
    }
    100% {
        transform: rotate(0deg);
    }
}