.demo3{
margin:300px 0 50px 300px
height: 100px;width: 100px;
border: 1px solid #000000;
background: #00ff00;
}
.demo3-display{
display: none;
height: 100%;width: 100%;
font-size: 25px;color: #0000f1;
background:rgba(246,152,30,0.5)
}
.demo3:hover .demo3-display{
display: block;
}