一张图片

http://code.google.com/images/sprites08132008.png

#gc-toc ul .tlw-plus, #gc-toc ol .tlw-plus, .treelist .tlw-plus {
	background-image:url(/images/sprites08132008.png);
	background-position:-28px -146px;
	height:9px;
	width:9px;
}
#gc-toc ul .tlw-minus, #gc-toc ol .tlw-minus, .treelist .tlw-minus {
	background-image:url(/images/sprites08132008.png);
	background-position:-28px -210px;
	height:9px;
	width:9px;
}
#gc-toc ul .tlw-plus:hover, #gc-toc ol .tlw-plus:hover, .treelist .tlw-plus:hover {
	background-image:url(/images/sprites08132008.png);
	background-position:-28px -344px;
	height:9px;
	width:9px;
}
#gc-toc ul .tlw-minus:hover, #gc-toc ol .tlw-minus:hover, .treelist .tlw-minus:hover {
	background-image:url(/images/sprites08132008.png);
	background-position:-28px -408px;
	height:9px;
	width:9px;
}