.BG1 {
position: fixed;
width: 100%;
height: 100vh;
background-repeat: repeat-y;
display: inherit;
justify-content: center;
align-items: center;
overflow: hidden;
z-index:-3;
-webkit-user-select: none;
-moz-user-select: none;
user-select: none;
}
.main-window {
position: fixed;
top: 0;
right: 0;
width: 100%;
height: 100%;
z-index: 999999;
}