.main{ font:12px/24px "Microsoft YaHei";position:relative; }
.main:after{ content:""; clear:both; display:table; }

#show{ width:360px; height:270px; overflow:hidden; position:relative; left:0; }
#show_mark{ position:absolute; top:0; left:0; width:200px; height:100px; background-color:#000; opacity:.5; filter:alpha(opacity=50); cursor:crosshair; border:1px solid #999; display:none; }
#zoom{ position:absolute; left:418px; top:0; z-index:3; width:352px; height:265px; display:none; overflow:hidden; border:1px solid #eee; }
#zoom img{ position:absolute; left:0; top:0; }