.area_group {
  display: flex;
  flex-wrap: wrap;
}
@media only screen and (min-width: 960px) {
  .area_group > div {
    width: calc((100% / 3) - (2em / 3));
    margin-right: 1em;
  }
  .area_group > div:nth-child(3n) {
    margin-right: 0;
  }
}
@media only screen and (min-width: 550px) and (max-width: 959px) {
  .area_group > div {
    width: calc((100% / 2) - (1em / 2));
    margin-right: 1em;
  }
  .area_group > div:nth-child(2n) {
    margin-right: 0;
  }
}
@media only screen and (max-width: 549px) {
  .area_group > div {
    width: 100%;
  }
}
.ad_site_flex {
  display: flex;
  flex-wrap: wrap;
}
.ad_site_flex > div {
  text-align: center;
}
.ad_site_flex > div a {
  text-align: center;
  display: inline-block;
}
@media only screen and (min-width: 768px) {
  .ad_site_flex > div {
    width: calc((100% / 2) - (1em / 2));
    margin-right: 1em;
  }
  .ad_site_flex > div:nth-child(2n) {
    margin-right: 0;
  }
}
@media only screen and (max-width: 767px) {
  .ad_site_flex > div {
    width: 100%;
    margin-bottom: 1em;
  }
}
.ad_site_flex > div img {
  border: solid 1px #ccc;
}