body#skillup .visual .imgbox {
  background: url("../images/curriculum/skillup/visual1.jpg") no-repeat center top;
  background-size: cover;
}

/* RWD
---------------------------------------------------------------- */
@media only screen and (max-width: 1280px) {
  body#skillup .visual .imgbox {
    background: url("../images/curriculum/skillup/visual2.jpg") no-repeat center top;
    background-size: cover;
  }
}
@media only screen and (max-width: 1100px) {
  body#skillup .visual .imgbox {
    background: url("../images/curriculum/skillup/visual3.jpg") no-repeat center top;
    background-size: cover;
  }
}