add global style sheet so that we don't need as many rules in accounttree.css

mailnews/base/prefs/resources/content/accounttree.xul

@@ -1,4 +1,5 @@
 <?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
 <?xml-stylesheet href="chrome://messenger/skin/" type="text/css"?>
 <?xml-stylesheet href="chrome://messenger/skin/accounttree.css" type="text/css"?>
 
@@ -14,17 +15,17 @@
 <window	xmlns:html="http://www.w3.org/TR/REC-html40"
 		xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 		xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-		style="width:100%">
+        style="width:100%">
 
 	<html:script language="JavaScript" src="AccountManager.js"/>
-	
+
 	<tree rdf:datasources="rdf:msgaccountmanager"
           onclick="showPage(event)" id="accounttree"
           style="height: 100%">
 
 	  <template>
 	  	<rule>
-                        <treechildren>
+            <treechildren>
 			<treeitem uri="...">
 		  		<treerow >
                     <treecell treeallowevents="true">
@@ -36,7 +37,7 @@
 					</treecell>
 		  		</treerow>
 			</treeitem>
-                        </treechildren>
+            </treechildren>
 		</rule>
 	  </template>
 
@@ -51,7 +52,7 @@
 
 	  <treechildren rdf:containment="http://home.netscape.com/NC-rdf#Settings">
 	    <treeitem id="msgaccounts:/" open="true"/>
-	  </treechildren>
+      </treechildren>
 	  
 	</tree>