.shiyan_leftbox li { float: left; height: 426px; margin-left: 4px; overflow-x: hidden; overflow-y: hidden; position: relative; width: 244px; } .shiyan_leftbox li a { float: left; height: 426px; width: 244px; } .shiyan_leftbox li a .one { float: left; height: 213px; left: 0; top: -213px; transition: all 0.5s; width: 244px; z-index: 4; } .shiyan_leftbox li a .two { bottom: -213px; float: left; height: 213px; left: 0; transition: all 0.5s; width: 244px; z-index: 4; } .shiyan_leftbox li a:hover .one { top: 0; } .shiyan_leftbox li a:hover .two { bottom: 0; } .shiyan_leftbox li a .pic { float: left; height: 426px; left: 244px; top: 0; transition: all 0.5s; width: 244px; z-index: 3; } .shiyan_leftbox li a:hover .pic { left: 0; }