body {
  font-size:20px;
}
img {
  width:500px;
}
.small {
  width:300px;
}
.mid {
  width:500px;
}
.heading {
  background-color: paleturquoise;
  padding-top:10px;
  padding-bottom: 10px;
  padding-left:10px;
}
pre {
  background-color: #f8f9fa; /* Light grey background */
  border: 1px solid #dee2e6; /* Bootstrap's border color */
  border-radius: .25rem; /* Bootstrap's border radius */
  padding: .25rem; /* Padding around the code */
}