.loader {
    border: 16px solid #575757;
    border-top: 16px solid #ff5e5e;
    border-radius: 50%;
    width: 120px;
    height: 120px;
    animation: spin 2s linear infinite;
    margin: 100px;
}

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