html {
height:100%;
}

body {
height:100%; 
}

a{
  transition: color 0.3s;
  text-decoration: none;
}

a:hover{
  color : #FF0000;
}

.imgbox {
height:100%;
width:100%;
background-image: url(rsc.jpg);
background-size: auto 100%;
background-position: center;
background-repeat: no-repeat;
}