.panel{
position: absolute;
top:0;
left:0;
display:flex;
justify-content: center;
align-items: center;
height:100%;
width: 100%;
transition: transform 300ms;
z-index:-1;
}
.panel div{  
display:flex;
flex-direction:column;
justify-content: center;
align-items: center;
background: beige;
width: 400px;
height:400px;
z-index:1000;
}
.panel[data-on='on'] 
{
transform: scale(1);
}
.panel[data-on='off'] 
{
transform: scale(0);
}