.box {
  width: 40%;
  margin: 0 auto;
  background: rgba(255,255,255,0.2);
  padding: 35px;
  border: 2px solid #fff;
  border-radius: 20px/50px;
  background-clip: padding-box;
  text-align: center;
}


.overlay {
position: fixed;
top: 0;
bottom: 0;
left: 0;
right: 0;
background: rgba(0, 0, 0, 0.7);
transition: opacity 500ms;
visibility: hidden;
opacity: 0;
}
.overlay:target {
visibility: visible;
opacity: 1;
}

.popup {
margin: 200px auto;
padding: 20px;
background: #fff;
border-radius: 5px;
width: 50%;
position: relative;
transition: all 5s ease-in-out;
}

.popup h2 {
margin-top: 0;
color: #333;
font-family: Tahoma, Arial, sans-serif;
}
.popup .close {
position: absolute;
top: 20px;
right: 30px;
transition: all 200ms;
font-size: 30px;
font-weight: bold;
text-decoration: none;
color: #333;
}
.popup .close:hover {
color: #d62c2a;
}
.popup .content {
max-height: 30%;
overflow: auto;
}

@media screen and (max-width: 700px){
.box{
  width: 70%;
}
.popup{
  width: 70%;
}
}


.infobulle {
  position: relative;  /* les .infobulle deviennent référents */
  cursor: help;
}

/* on génère un élément :after lors du survol et du focus :*/

.infobulle:hover::after,
.infobulle:focus::after {
  content: attr(aria-label);  /* on affiche aria-label */
  position: absolute;
  top: -2em;
  transform: translateX(-50%); /* on centre horizontalement  */
  color:white;
  padding:5px;
  background-color:#d62c2a;
  z-index: 1; /* pour s'afficher au dessus des éléments en position relative */
  white-space: nowrap;  /* on interdit le retour à la ligne */
  opacity: 0.7;
  border-radius:10px;
}