body{
  background-color: #ececec;
}
.topImg{
  width: 100%;
}
.mainDiv{
  width: 90%;
  display: flex;
  flex-flow: wrap;
  align-items: center;
  justify-content: space-around;
  margin: 0 auto;
  margin-top: 1rem;
}
.mainDiv > a{
  width: calc((100% - 2.5rem)/2);
  padding: 0.5rem;
  background-color: #fff;
  margin-bottom: 1%;
}
.mainDiv > a > img{
  width: 100%;
  display: block;
  vertical-align:baseline;
}