.accordion {
  margin-left: auto;
  margin-right: auto;
  margin-top: 30px;
  max-width: 930px;
  position: relative;
  width: 100%;
}
.accordion-title {
  color: #fff;
  cursor: pointer;
  font-size: 16px;
  padding: 10px 20px;
}
.accordion-content {
  display: none;
  padding: 10px 10px;
}
.accordion-content p {
  font-size: 13px;
  line-height: 1.5;
}
.accordion-content img {
  width: 750px;
  max-width: 100%;
  margin: 0 auto;
  padding: 4px;
}
/* タイトルの背景色 */
.accordion-item:nth-of-type(1) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(2) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(3) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(4) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(5) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(6) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(7) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(8) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(9) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(10) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(11) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(12) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(13) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(14) .accordion-title {
  background-color: #666c70;
}
.accordion-item:nth-of-type(15) .accordion-title {
  background-color: #666c70;
}
/* コンテンツボックスの枠線 */
.accordion-item:nth-of-type(1) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(2) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(3) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(4) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(5) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(6) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(7) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(8) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(9) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(10) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(11) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(12) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(13) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(14) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
.accordion-item:nth-of-type(15) .accordion-content {
  border-bottom: 2px solid #666c70;
  border-left: 2px solid #666c70;
  border-right: 2px solid #666c70;
}
/* 矢印 */
.accordion-title {
  position: relative;
}
.accordion-title::after {
  border-right: solid 2px #fff;
  border-top: solid 2px #fff;
  content: "";
  display: block;
  height: 8px;
  position: absolute;
  right: 25px;
  top: 38%;
  transform: rotate(135deg);
  transition: transform .3s ease-in-out, top .3s ease-in-out;
  width: 8px;
}
.accordion-title.open::after {
  top: 45%;
  transform: rotate(-45deg);
}