The best solution to make an "iframe" responsive and fit with all device screens , simply apply this code (working great with Games sites):
iframe::-webkit-scrollbar{display:none}
.iframe{background:#fff;overflow:hidden}
.iframe iframe{width:100%;height:540px;border:0;display:block}
.iframe-content{position:absolute;width:100%;height:540px;overflow:auto;top:0;bottom:0;-webkit-overflow-scrolling:touch}
@media screen and (max-width:992px){.iframe iframe{height:720px}}
@media screen and (max-width:768px){.iframe iframe{height:720px}}
@media screen and (max-width:720px){.iframe iframe{height:720px}}
@media screen and (max-width:479px){.iframe iframe{height:480px}}
@media screen and (max-height:400px){.iframe iframe{height:360px}}
If you're looking for a responsive games container fit with all devices apply this code which uses advanced CSS @media queries.