body {
  background-color: powderblue;
}
h1 {
  color: DarkMagenta;
  font-family: verdana;

  div {
    width: 320px;
    height: 50px;
    padding: 10px;
    border: 5px solid gray;
    margin: 0;
  }
}

p {
  color: red;
}

a {
  color: red;
}

.collapsible {
  background-color: #777;
  color: white;
  cursor: pointer;
  padding: 18px;
  width: 100%;
  border: none;
  text-align: left;
  outline: none;
  font-size: 15px;
}

.active, .collapsible:hover {
  background-color: DarkMagenta;
}

.content {
  padding: 0 18px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.2s ease-out;
  background-color: #f1f1f1;
}
img {
  width: 100%;
  height: auto;
}