html, body, app {
    height: 100%;
    padding: 0;
    margin: 0;
}
app loader {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 10000;
    width: 100%;
    height: 100%;
    background-color: #fff;
    display: flex;
    justify-content: center;
    align-items: center;
}
app loader progress::-webkit-progress-value {
    transition: all 0.5s;
}