/* --- 上へ戻るボタン（上へ・下へボタン）20250828 --- */
#backToTopCSS {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 100;
  display: block;
  background-color: #333;
  color: #fff;
  padding: 10px 15px;
  border-radius: 50%;
  font-size: 20px;
  text-decoration: none;
  box-shadow: 0 2px 5px rgba(0,0,0,0.3);
}
#backToTopCSS:hover {
  background-color: #555;
}

/* --- 下へ行くボタン --- */
#goToBottomCSS {
  position: fixed;
  bottom: 20px;
  left: 20px;
  z-index: 100;
  display: block;
  background-color: #333;
  color: #fff;
  padding: 10px 15px;
  border-radius: 50%;
  font-size: 20px;
  text-decoration: none;
  box-shadow: 0 2px 5px rgba(0,0,0,0.3);
}
#goToBottomCSS:hover {
  background-color: #555;
}