.spinner {
    border: 2px solid rgba(0, 0, 0, 0.1);
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border-left: 2px solid #fff;
    border-bottom: 2px solid #fff;
    animation: spin 1s linear infinite;
    position: relative;
    top: 50%;
    left:  calc(50% - 10px);
    transform: translate(-50%, -50%);
}
 

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