html {
 overflow: auto;
}
 
html, body, iframe {
 margin: 0px; 
 padding: 0px; 
 height: 100%; 
 border: none;
}

.fullscreen {
 display: block; 
 width: 100%; 
 height: 100%;
 border: none; 
 overflow-y: auto; 
 overflow-x: hidden;
 margin: 0;
}