html {
  background-color : black ;
  background-image : url('http://room-decorating-ideas.com/wp-content/uploads/2012/06/Rubber-Duck.jpg');
  background-size : cover;
  background-attachment : fixed;
}
.page-header {
  background-color : #222222;
  color : #FFFFFF ;
  padding : 20px ;
}
.gallery {
  background-color : #222222;
  padding : 30px ;
  width : 700px;
  margin: 0 auto;
  margin-top: 30px;
  text-align: center;
}
.gallery img {
  height : 100px;
  border-width : 5px;
  border-color : #FFFFFF;
  border-style : solid ;
  box-shadow : 3px 3px 5px 6px #000000;
  margin : 5px;
}
.main-menu {
  background : #FF0000;
}
.main-menu a {
    background-color: #00FF00;
    border-color: #FFFFFF;
    font-weight: bold;
    display: inline-block;
    padding: 5px 10px;
}
.main-menu a:hover {
  background-color : #FFFFFF;
  color : #FFFFFF;
}