html, body{
  height: 100%;
}
body { 
    background-image: url(L--1920x1200.jpg) ;
    background-position: center center;
    background-repeat:  no-repeat;
    background-attachment: fixed;
    background-size:  cover;
    background-color: #999;
}

div, body{
  margin: 0;
  padding: 0;
  font-family: exo, sans-serif;
  
}
.wrapper {
  height: 100%; 
  width: 100%; 
}

.message {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  width: 100%; 
  height:20%;
  bottom: 0; 
  display: block;
  position: absolute;
  background-color: rgba(0,0,0,0.6);
  color: #fff;
  padding: 0.5em;
}