div.gallery {
  border: 0px solid #ccc;
}

div.gallery:hover {
  border: 0px solid #777;
}

div.gallery img {
  width: 100%;
  height: auto;
}

div.desc {
  font-size: small;
  font-weight: bold;
  padding: 1px;
  text-align: center;
}

* {
  box-sizing: border-box;
}

.responsive {
  padding: 0 16px;
  float: left;
  width: 24.99999%;
}

@media only screen and (max-width: 700px) {
  .responsive {
    width: 49.99999%;
    margin: 6px 0;
  }
}

@media only screen and (max-width: 500px) {
  .responsive {
    width: 100%;
  }
}

.clearfix:after {
  content: "";
  display: table;
  clear: both;
}

.zoom {
  padding: 1px;
  transition: transform .4s;
}

.zoom:hover {
  transform: scale(1.2);
}

.flip-box {
  background-color: transparent;
  width: 350px;
  height: 250px;
  border: 0px solid #f1f1f1;
  perspective: 1000px;
}

.flip-box-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.8s;
  transform-style: preserve-3d;
}

.flip-box:hover .flip-box-inner {
  transform: rotateY(180deg);
}

.flip-box-front, .flip-box-back {
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
}

.flip-box-front {
  background-color: transparent;
  color: black;
}

.flip-box-back {
  background-color: transparent;
  color: white;
  transform: rotateY(180deg);
}

.img-effect {
      transition: 0.4s;
      filter: grayscale(100%);
    }

    .img-effect:hover {
      filter: grayscale(0%);
    }