#masque1, #masque2, #masque3, #masque4, #masque5, #masque6, #masque7, #masque8, #masque9, #masque10, #masque11, #masque12, #masque13, #masque14, #masque15, #masque16, #masque17, #masque18, #masque19, #masque20 {
    display: none;
    position: fixed;
    top:0; right:0; bottom:0; left:0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1000;
}
#masque1:target, #masque2:target, #masque3:target, #masque4:target, #masque5:target, #masque6:target, #masque7:target, #masque8:target, #masque9:target, #masque10:target, #masque11:target, #masque12:target, #masque13:target, #masque14:target, #masque15:target, #masque16:target, #masque17:target, #masque18:target, #masque19:target, #masque20:target {
    display: block;
}

.fenetre-modale {
    background: #fff;
    padding: 20px;
    border: 10px solid #bbb;
    position: relative; 
    margin: 10% auto;
    width: 50%;
	height: 400px;
    box-shadow: 0px 0px 20px #000;
    border-radius: 5px;
}
img.batiment-detail {
	float: right;
	margin: 0 0 0 20px;
}
img.bouton-fermer-fenetre-modale {
    float: right;
    margin: -55px -55px 0 0;
}