/* [GALLERY] */
#gallery {
  max-width: 1200px;
  margin: 0 auto;
}

#gallery img {
  box-sizing: border-box;
  width: 25%;
  max-height: 150px;
  padding: 5px;
  /* fill, contain, cover, scale-down : use whichever you like */
  object-fit: cover;
}

/* [RESPONSIVE GALLERY] */
@media screen and (max-width: 850px) {
  #gallery img {
    width: 33%;
  }
}

@media screen and (max-width: 640px) {
  #gallery img {
    width: 50%;
  }
}