.penta-loading {
    display: inline-block;
    width: 1em;
    height: 1em;
    border: 2px solid #fff;
    border-top: 2px gray solid;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
    margin-left: 8px;
    vertical-align: middle;
}

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