HTMLify

body {
    background-color: #1a1a1a;
}

.loader {
    position: absolute;
    top: 50%;
    left: 50%;
    margin: -90px 0 0 -90px;
}

.circle {
    position: absolute;
    border: 3px solid transparent;
    border-top-color: #9ee925;
    border-radius: 50%;
    animation: rotate linear infinite;
}

.circle.one {
    height: 50px;
    width: 50px;
    left: 50px;
    top: 50px;
    animation-duration: 0.85s;
}

.circle.two {
    height: 75px;
    width: 75px;
    top: 38px;
    left: 38px;
    animation-duration: 0.95s;
}

.circle.three {
    height: 100px;
    width: 100px;
    top: 25px;
    left: 25px;
    animation-duration: 1.05s;
}

@keyframes rotate {
    from {
        transform: rotateZ(360deg);
    }

    to {
        transform: rotateZ(0deg);
    }
}