html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #f0f0f0;
}

.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
  grid-gap: 10px;
  width: 100%;
  max-width: 600px;
}

.gallery img {
  width: 100%;
  height: auto;
  object-fit: cover;
}