.readmore-box{ 
    display: none;
    padding: 20px;
    width: auto;
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: #fff;
    box-shadow: 0 -20px 25px #fff;
    z-index:10;
}
.readmore-box > .readmorebutton{
    margin: 0 auto;
    display: block;
}   
#content-area.-collapse {
    max-height: 450px;
    overflow: hidden;
    position: relative;
}

#content-area.-collapse > .readmore-box{
    display: block;
}