.loader {
    border: 16px solid #f3f3f3; /* Light grey */
    border-top: 16px solid #3498db; /* Blue */
    border-radius: 50%;
    width: 100px;
    height: 100px;
    position:fixed;
    z-index:2000;
    animation: spin 1s linear infinite;
}

.loader.internal {
    top: 42%;
    left: 46%;
}

.loader.hide, .backdrop.hide {
    display:none;
}

.backdrop {
    background-color: rgba(0, 0, 0, 0.6);
    position:fixed;
    z-index:1500;
    width:100%;
    height:100vh;
}

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