body {
  font-family: sans-serif;
  line-height: 1.4;
  padding: 20px;
  max-width: 1200px;
  margin: 0 auto;
  text-align: center;
  background-color: BurlyWood;
}

.grid__col-sizer,
.photo-item {
  width: 32%;
}

.grid__gutter-sizer {
  width: 2%;
}

.photo-item {
  margin-bottom: 10px;
  float: left;
}

.photo-item__image {
  display: block;
  max-width: 100%;
}