.login_button {
    position: relative;
}

.login_button.is-loading {
    color: transparent !important;
    pointer-events: none;
}

.login_button.is-loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 22px;
    height: 22px;
    margin: -11px 0 0 -11px;
    border: 3px solid rgba(255, 255, 255, 0.35);
    border-top-color: #fff;
    border-radius: 50%;
    animation: authorization-spin 0.7s linear infinite;
}

@keyframes authorization-spin {
    to { transform: rotate(360deg); }
}