#spinner-div{
    position: fixed;
    display:none;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    text-align: center;
    background-color: rgba(255, 255, 255, 0.8);
    z-index: 999;
}

.spinner-border-big {
    display: inline-block;
    width: 5rem;
    height: 5rem;
    vertical-align: text-bottom;
    border: 0.5em solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    -webkit-animation: 0.75s linear infinite spinner-border;
            animation: 0.75s linear infinite spinner-border;
    position: relative;
    top: calc(50% - 5rem);
}