html,body{
    margin:0;
    padding:0;
    height:100%;
}

#player{
    width:100%;
    height:100%;
}
#alertMessage{
    margin:50px;
    text-align: center;
}
#gallery{
    height:100%;
    text-align: center;
    background:#444;
}
#gallery img{
    max-width: 100%;
    max-height:100%;
    display: block;
    margin:auto;
}