.button-spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(0,0,0,0.2);
    border-top-color: rgba(0,0,0,0.6);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
    vertical-align: middle;
    margin-right: 1rem;
}

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