.ButtonSpinner {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 1.3em;
}
.ButtonSpinner div {
    background: gray;
    width: 8px;
    height: 8px;
    border-radius: 4px;
    animation: lds_spinner 3s linear infinite;
    opacity: 0;
    margin: 0 1px;
}
.ButtonSpinner div:nth-child(2) {
    animation-delay: 0.5s;
}
.ButtonSpinner div:nth-child(3) {
    animation-delay: 1s;
}

@keyframes lds_spinner {
    0% {
        opacity: 1;
    }
    20% {
        opacity: 1;
    }
    34% {
        opacity: 0;
    }
    100% {
        opacity: 0;
    }
}