/* (A) GALLERY WRAPPER */
/* (A1) BIG SCREENS - 3 IMAGES PER ROW */
.gallery {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-gap: 10px;
  max-width: 1200px;
  margin: 0 auto; /* horizontal center */
}

/* (A2) SMALL SCREENS - 2 IMAGES PER ROW */
@media screen and (max-width: 640px) {
  .gallery { grid-template-columns: repeat(2, 1fr); }
  .gallery img { height: 200px; }
}

/* (B) THUMBNAILS */
.gallery img {
  width: 100%;
  height: 250px;
  object-fit: cover; /* fill | contain | cover | scale-down */
  border: 1px solid #cdcdcd;
  cursor: pointer;
}

/* (C) FULLSCREEN IMAGE */
.gallery img.full {
  position: fixed;
  top: 0; left: 0; z-index: 999;
  width: 100vw; height: 100vh;
  object-fit: scale-down; /* fill | contain | cover | scale-down */
  border: 0;
  background: #fff;
  overflow-x: hidden;
}

/* (D) OPTIONAL ANIMATION */
.gallery { overflow-x: hidden; }
.gallery img.full {
  animation: fadeIn ease 0.5s;
  -webkit-animation: fadeIn ease 0.5s;
  -moz-animation: fadeIn ease 0.5s;
  -o-animation: fadeIn ease 0.5s;
  -ms-animation: fadeIn ease 0.5s;
}
@keyframes fadeIn {
  0% {opacity:0;}
  100% {opacity:1;}
}

@-moz-keyframes fadeIn {
  0% {opacity:0;}
  100% {opacity:1;}
}

@-webkit-keyframes fadeIn {
  0% {opacity:0;}
  100% {opacity:1;}
}

@-o-keyframes fadeIn {
  0% {opacity:0;}
  100% {opacity:1;}
}

@-ms-keyframes fadeIn {
  0% {opacity:0;}
  100% {opacity:1;}
}