body {
  font-family: sans-serif;
  text-align: center;
  background: #fafafa;
  color: #222;
}

h1 {
  margin: 20px 0;
}

ul#gallery {
  list-style: none;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, 60px);
  gap: 10px;
  justify-content: center;
}

ul#gallery li img {
  width: 50px;
  border-radius: 5px;
  box-shadow: 0 0 5px rgba(0,0,0,0.2);
}