pjs/mail/base/content/aboutDialog.css

#aboutDialog {
  padding: 0px 0px 10px 0px;
}

#clientBox {
  background-color: #FFFFFF;
  background-image: url("chrome://branding/content/about-thunderbird.png");
  background-repeat: no-repeat;
  padding-top: 216px;
  color: #000000;
}

#versionWrapper {
  margin: 0px 0px 3px 20px;
}

#versionField {
  background-color: #FFFFFF;
  -moz-appearance: none;
  border: none;
  font-weight: bold;
  color: #909090;
}

#copyright {
  color: #909090;
  margin: 0px 0px 3px 20px;
}

#groove {
  margin-top: 0px;
}

#creditsIframe {
   cursor: default;
   -moz-user-select: none;
}

button[dlgtype="extra2"] {
  margin-left: 13px;
}
 
button[dlgtype="accept"] {
  margin-right: 13px;
}