@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

notification {
	color: #ffffff;
	background-color: rgb(128,200,210);
	border-top: 0px solid transparent;
	border-bottom: 1px solid #CCCCCC;
	border-left: 0px solid transparent;
	border-right: 0px solid transparent;
}
notification[type="info"] {}
notification[type="critical"] {
	background-color: red;
}
.notification-inner {
	padding: 1px;
	border: none !important;
}
.messageImage {
	width: 16px;
	height: 16px;
	margin-top: 0px;
	margin-bottom: 0px;
	-moz-margin-start: 5px;
	-moz-margin-end: 1px;
}
.messageText {
	font-weight: bold;
	margin: 5px !important;
}
.messageButton {
	margin: 0px 5px;
}
.messageCloseButton {
	-moz-appearance: none;
	padding: 4px 2px;
	border: none !important;
}

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

notification {
	color: #ffffff;
	background-color: rgb(128,200,210);
	border-top: 0px solid transparent;
	border-bottom: 1px solid #CCCCCC;
	border-left: 0px solid transparent;
	border-right: 0px solid transparent;
}
notification[type="info"] {}
notification[type="critical"] {
	background-color: red;
}
.notification-inner {
	padding: 1px;
	border: none !important;
}
.messageText > .text-link {
  color: inherit !important;
  text-decoration: underline;
}
.messageImage {
	width: 16px;
	height: 16px;
	margin-top: 0px;
	margin-bottom: 0px;
	-moz-margin-start: 5px;
	-moz-margin-end: 1px;
}
.messageText {
	font-weight: bold;
	margin: 5px !important;
}
.messageButton {
	margin: 0px 5px;
}
.messageCloseButton {
	-moz-appearance: none;
	padding: 4px 2px;
	border: none !important;
}
.popup-notification-learnmore-link {
  margin-top: 1em !important;
}
.popup-notification-learnmore-link:not([href]) {
  display: none;
}

Fix learn more links on Mac
Fix learn more links on Mac