html, body {
    width: 100%;
    height: 100%;
    margin: 0;
    background-color: lightgrey;
    padding: 0;
    overflow: hidden;
}

.loader,
.loader:after {
    border-radius: 50%;
    width: 10em;
    height: 10em;
}
.loader {
    margin: 100px auto;
    font-size: 10px;
    position: relative;
    border-top: 1.5em solid rgba(255, 255, 255, 0.2);
    border-right: 1.5em solid rgba(255, 255, 255, 0.2);
    border-bottom: 1.5em solid rgba(255, 255, 255, 0.2);
    border-left: 1.5em solid #ffffff;
    animation: loadingAnimation 1.5s infinite linear;
}
@keyframes loadingAnimation {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}