details,
summary {
  display: inline;
  vertical-align: super;
  font-size: 0.75rem;
  padding: 0 0.125rem;
}

summary {
  cursor: pointer;
}

.details-content {
  position: fixed;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  max-width: 100%;
  padding: 1rem;
  font-size: 1.2rem;
  background: white;
  box-shadow: 0 0 100px black;
  border-top-left-radius: 4px;
  border-top-right-radius: 4px;
}

#mydiv {
  text-align:center;
  padding:40px;
  background-color:lightblue;
  font-family:"Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}