#main_title {
  position: relative;
  background-image: url("../images/common/common-bg-pc.png");
  background-repeat: no-repeat;
  background-size: cover;
}
#main_title::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0,0,0,0.4);
}
#main_title h1 {
  position: relative;
  color: #fff;
  z-index: 1;
}
.site_content .cat_top { margin-top: 45px; }
@media screen and (max-width: 991px){
  #main_title { background-image: url("../images/common/common-bg-sp.png"); }
}