[Seva1986]

Триви,

div#outer {
width:100%;
height:300px;
background-color:#F00;
border: 1px solid;
overflow-y:scroll;
position:relative;
}
div#topic {
position:absolute;
bottom:0;
left:0;
right:0;
background-color:#0F0;
border: 1px solid;