window { 
 display: block; 
} 

tree { 
 display: table; 
 background-color: #eeeeee; 
 border: none; 
 border-spacing: 0px; 
 border-collapse: collapse; 
} 

treerow { 
 display: table-row; 
} 

treehead { 
 display: table-header-group; 
} 

treebody { 
 display: table-row-group; 

} 

treecell { 
 display: table-cell; 
} 

treehead treerow treecell { 
 background-color: #a0a0a0; 
 border: thin black solid; 
}