*{
    margin:0;
    padding:0;
}
html{
    width:100%;
    min-height:100%;
}
body{
    width:100%;
    min-height:100%;
}
#page{
    position:relative;
    width:100%;height:100%;
    background-image:linear-gradient(90deg,blue,white,white,red);
}
#page #stream{
    width:90%;
    height:90%;
    position:absolute;
    left:5%;top:5%;
}