code de flo pour image background plus responsive
""<style>
.fullpage {
  margin:-1rem; // car #ym-main a un padding de 1rem
  margin-bottom:1rem;
  height:100vh; 
  width:100vw;
  display:block;
}
@media (min-width: 992px) {
  .fullpage { margin-top:-1.5rem;margin-left:-1.5rem;margin-right:-1.5rem; }
}
.fullpage img{
  height: 100vh;
  width: 100vw;
  border-radius:0;
  object-fit: cover;
}</style>""