.youtube-container { 
display: block; 
margin: 20px auto; 
width: 100%; 
max-width: 600px; 
}

.youtube-player { 
display: block; 
width: 100%; /* assuming that the video has a 16:9 ratio */ 
padding-bottom: 56.25%; 
overflow: hidden; 
position: relative; 
width: 100%; 
height: 100%; 
cursor: hand; 
cursor: pointer; 
display: block; 
}

img.youtube-thumb { 
bottom: 0; 
display: block; 
left: 0; 
margin: auto; 
max-width: 100%; 
width: 100%; 
position: absolute; 
right: 0; 
top: 0; 
height: auto 
}

div.play-button { 
height: 50px; 
width: 71px; 
left: 50%; 
top: 50%; 
margin-left: -36px; 
margin-top: -36px; 
position: absolute; 
background: url("http://www.peacecup.upf-ticino.ch/img/play.svg") no-repeat; 
}

#youtube-iframe { 
width: 100%; 
height: 100%; 
position: absolute; 
top: 0; 
left: 0; 
}