body {
  background:#111;
  color:#ddd;
}
#main {
  width:90%;
  margin:auto;
}
.photos {
  display:inline-block;
  background:#222;
  padding:8px;
  margin:10px;
  border-radius:6px;
}

.photos img {
  width:200px;
  height:auto;
  border-radius:4px;
  box-shadow:0 0 8px #000;
}

.photos img:hover {
  opacity:.8;
}