._wrapper {
   width: 100%;
   height: 100%;
   margin: 0 auto;
   background: #CCC
}

.h_iframe {
   position: relative;
}

.h_iframe .ratio {
   display: block;
   width: 100%;
   height: auto;
}

.h_iframe iframe {
   position: absolute;
   top: 0;
   left: 0;
   width: 100%;
   height: 100%;
}