erpnext/docs/assets/css/docs-erp.css

.embed-container { 
    position: relative; 
    padding-bottom: 56.25%; 
    height: 0; 
    overflow: hidden; 
    max-width: 100%; } 
    
.embed-container iframe, .embed-container object, .embed-container embed { 
    position: absolute; 
    top: 0; 
    left: 0; 
    width: 100%; 
    height: 100%; 
}