@-webkit-keyframes spinner-border {
    to {
        -webkit-transform: rotate(360deg);
        transform: rotate(360deg);
    }
}

@keyframes spinner-border {
    to {
        -webkit-transform: rotate(360deg);
        transform: rotate(360deg);
    }
}

.center-screen {
    position: absolute;
    width: 100%;
    height: 100%;
}

.spinner-border {
    display: inline-block;
    width: 5rem;
    height: 5rem;
    vertical-align: text-bottom;
    border: 0.25em solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    -webkit-animation: spinner-border .75s linear infinite;
    animation: spinner-border .75s linear infinite;
    position: absolute;
    top: 50%;
    left: 50%;
    margin-top: -50px;
    margin-left: -50px;
}

.spinner-border-sm {
    width: 1rem;
    height: 1rem;
    border-width: 0.2em;
}