#main div.acc_news div:first-child {
  border: 1px solid #94e394;
  background: linear-gradient(to bottom, #ebffeb 0%, #c1ffc1 100%);
}

#main section div.acc_news {
  box-shadow: 1px 2px 5px rgba(0, 0, 0, 0.1);
  border-radius: 7px;
  margin-bottom: 10px;
}
#main section div.acc_news div:first-child {
  border-radius: 7px;
  padding: 10px;
  position: relative;
}
#main section div.acc_news div:first-child.open {
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0;
}

#main section div.acc_news div:first-child .main-acc {
  color: #40566a;
  cursor: pointer;
  font-size: 1.7rem;
  position: absolute;
  right: 10px;
  text-align: right;
  top: 4px;
  width: 100%;
}

/*直近の年のみ展開した状態にする*/
#main section div.acc_news:first-child div:nth-child(2) {
  /*display: none;*/
  border: 1px solid #777;
  border-radius: 7px;
  border-top-left-radius: 0;
  border-top-right-radius: 0;
  border-top: 0;
}
/*直近以外の年は展開しない状態にする*/
#main section div.acc_news:not(:first-child) div:nth-child(2) {
  display: none;
  border: 1px solid #777;
  border-radius: 7px;
  border-top-left-radius: 0;
  border-top-right-radius: 0;
  border-top: 0;
}