body {
    --mamarge: 10px;
    margin: var(--mamarge);
    background-image: url(images/fond.jpg);
    /* background-size: cover; */
    background-size: 100vw auto;
    background-repeat: repeat;
}
svg {
    position: fixed;
    width: calc(100vw - var(--mamarge) * 2);
    height: calc(100vh - var(--mamarge) * 2);
}
img {
    position: fixed;
    width: calc(100vw - var(--mamarge) * 2);
    height: calc(100vh - var(--mamarge) * 2);
}
path {
    fill: transparent;
    cursor: pointer;
}
rect {
    fill: transparent;
    cursor: pointer;
}
polygon{
    fill: transparent;
    cursor: pointer;
}
/* image avec la class survol cachée */
.survol {
    opacity: 0;
 }
  /* quand le a est survolé, la class survol n’est plus cachée */
 svg:has(a:hover) .survol {
     opacity: 1;
}