main {

  margin: 0 auto;
}
summary {
  font-size: 1.25rem;
  font-weight: 600;
  background-color:#43ba7f;
  color: #fff;
  padding: 1rem;
  margin-bottom: 1rem;
  outline: none;
  border-radius: 0.25rem;
  text-align: left;
  cursor: pointer;
  position: relative;
}
p { text-align: left; }
details[open] summary ~ * {
  animation: sweep .5s ease-in-out;
}
@keyframes sweep {
  0%    {opacity: 0; margin-top: -10px}
  100%  {opacity: 1; margin-top: 0px}
}
details > summary::after {
  position: absolute;
  content: "+";
  right: 20px;
}
details[open] > summary::after {
  position: absolute;
  content: "-";
  right: 20px;
}
details > summary::-webkit-details-marker {
  display: none;
}