12. Warstwy - własność z-index

<style>
#demo1,
#demo2,
#demo3,
#demo4,
#demo5,
#demo6{
    width:200px;
    height:200px;
    border:1px solid black;
    position:absolute;
    padding:5px;
    opacity:.8;
}
#demo1{top:120px; right:20px; background:#757c84; z-index:3}
#demo2{top:150px; right:50px; background:#eef0e9; z-index:4}
#demo3{top:180px; right:80px; background:#e6b790; z-index:-1}
#demo4{top:210px; right:110px; background:#a55f41; z-index:2}
#demo5{top:240px; right:140px; background:#503434; z-index:1}
#demo6{top:270px; right:170px; background:#757c84; z-index:0}
</style>

<div id="demo1">demo 1</div>
<div id="demo2">demo 2</div>
<div id="demo3">demo 3</div>
<div id="demo4">demo 4</div>
<div id="demo5">demo 5</div>
<div id="demo6">demo 6</div>
demo 1
demo 2
demo 3
demo 4
demo 5
demo 6