.s1 {
	background: url("/app/images/section-cadre.png") no-repeat center center;
}
.s2 {
	background: url("/app/images/section-cadre.png") no-repeat center center;
}
.s3 {
	background: url("/app/images/section3-cadre.png") no-repeat center center;
}
.s4 {
	background: url("/app/images/section4-cadre.png") no-repeat center center;
}