p {
    text-align: center;
}
.choosen {
    text-align: center;
    color: red;
}
.middlea {
    display: flex;
    justify-content: center;
    align-items: center;
}
h1 {
    color: greenyellow;
    text-align: center;
}
h3 {
    color: cyan;
    text-align: center;
}
.img-center {
    display: block;
    margin:0 auto;
}
iframe {
    display: block;
    margin:0 auto;
}
.rectangle-back{
    width: 850px;
    height: 9999px;
    overflow:hidden;
    background-color: cornsilk;
    z-index: -1;
    position: fixed;
    position: fixed;
    left:50%;
    top:50%;
    transform:translate(-50%,-50%);
}
.backGround {
    z-index: -1;
    overflow: clip;
    position: fixed;
    animation: move 5s infinite alternate-reverse ease-in-out;
}
@keyframes move {
    0% {
        left: -60%;
        top: -60%;
    }
    100% {
        left: 0%;
        top: 0%;
    }
}