html,
body {
  background: #fffdea;
  height: 100%
}

img {
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: -384px;
  margin-left: -512px;
}

#imprint {
  position: fixed;
  bottom: 1%;
  left: 1%;
  padding: .5rem;
  background: rgba(255, 253, 234, 0.6);

}

details {
  max-width: 800px;
}
details[open]>summary::after {
  transform: rotate(135deg);
}
summary {
  position: relative;
  max-width: 800px;
  margin-bottom: 1rem;
  padding-bottom: .5rem;
  border-bottom: 1px solid currentColor;
}
summary::marker,
summary::-webkit-details-marker {
  color: transparent;
}
summary::after {
  content: "+";
  position: absolute;
  font-size: 2rem;
  font-weight: bold;
  right: 0;
  top: -.5rem;
  transition: all 0.5s;
  margin-right: 1rem;
}