body:after {
    content: 'Você está no ambiente sandbox!';
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: #ffd900;
    font-weight: bold;
    padding: 3px;
    color: #000;
    border-bottom: 1px solid #ddb500;
    z-index: 9999;
    text-align: center;
}