body:after {
    content: 'Test Site';
    background-color: #b60000;
    color: #fff;
    font-weight: bold;
    position: fixed;
    bottom: 0;
    left: 0;
    pointer-events: none;
    z-index: 999999;
    opacity: .5;
    font-size: 10px;
    padding: 4px;
    font-family: Arial, sans-serif;
}