MediaWiki:Common.css

.mw-parser-output .mw-file-element,
.mw-parser-output .thumbimage,
.mw-parser-output img {
  max-width: 100%;
  height: auto;
}

#wpBio, 
#wpNewBio,
.mw-confirmaccount-type-0, 
.mw-confirmaccount-body-0 {
    background-color: transparent !important;
}