div#content_box div.content_in_box {
  position: absolute;
  left: 435px;
  top: 81px;
  width: 430px;
  height: 530px;
  color: #ffffff;
}

/* sample内のメニュー */
div#content_box div#sample_menu {
  position: absolute;
  top: 545px;
  left: 170px;
  width: 320px;
}

div#content_box div#sample_menu img {
  float: left;
  margin: 2px;
}

.sample-list {
  display: flex;
  margin: 0;
  padding: 0;
  flex-flow: row;
  flex-wrap: wrap;
  justify-content: flex-start;
  list-style: none;
}

.sample-list li:hover {
  opacity: 0.7;
}

.sample-list li {
  width: 90px;
  height: 70px;
}

.sample-list li + li {
  margin-top: 23px;
  margin-left: 23px;
}

.sample-list li:nth-child(-n + 4) {
  margin-top: 0;
}

.sample-list li:nth-child(4n + 1) {
  margin-left: 0;
}

.sample-list li img {
  width: 100%;
}