gecko-dev/rdf/resources/bookmarks.css

window { 
 display: block; 
} 

tree { 
 display: table; 
 background-color: #FFFFFF; 
 border: none; 
 border-spacing: 0px; 
 border-collapse: collapse; 
 width: 100%;
} 

treeitem { 
 display: table-row; 
} 

treehead { 
 display: table-header-group; 
} 

treebody { 
 display: table-row-group; 
} 

treecell { 
 display: table-cell; 
} 

treehead treeitem treecell { 
 background-color: #c0c0c0; 
 border: outset 1px;
 border-color: white #707070 #707070 white;
 padding-left: 4px;
}