Drop-down frame

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">
　　
@charset "Utf-8";/* CSS Document *//* Small mine */.a{width:80px;height:40px;background-color: #090;p Osition:absolute;border : 1px solid black;left:80px;top:100px;} #a/* out of partially hidden */{overflow:hidden;} #a: hover/* mouse on the top display */{overflow:visible}.a1{width:80px;height:120px;border:1px solid black;left:0px;top:40px; Position:absolute;}. A2{width:80px;height:40px;background-color: #F00;p osition:absolute;border:1px solid black;left:0px;top:0px;} #a2 {Overflow:hidden;} #a2: hover{overflow:visible}.a21{width:80px;height:120px;position:absolute;border:1px Solid black;left:80px;top:0     Px;background-color: #F00;}                . a22 {width:80px;            height:40px;              Background-color: #F00;                 Position:absolute;                 BORDER:1PX solid black;                 left:0px;                           top:0px; }.a32{width:80px;height:40px;background-color: #F00;p osition:absolute;border:1px solid black;left:0px;top:40px;}. A42{width:80px;height:40px;background-color: #F00;position:absolute;border:1px solid black;left:0px;top:80px;}. A3{width:80px;height:40px;background-color: #F0F;p osition:absolute;border:1px solid black;left:0px;top:40px;} #a3 {Overflow:hidden;} #a3: hover{overflow:visible}.a31{width:80px;height:120px;position:absolute;border:1px Solid black;left:80px;top:0 Px;background-color: #F0F;}. A4{width:80px;height:40px;background-color: #F69;p osition:absolute;border:1px solid black;left:0px;top:80px;} #a4 {Overflow:hidden;} #a4: hover{overflow:visible}.a41{width:80px;height:120px;border:1px Solid black;position:absolute;left:80px;top:0            px Background-color: #F69;}
　　
Drop-down frame