@media screen and (min-width: 640px) {
  .os .os-child-header-inner {
    background-image: url("../img/mv.jpg");
  }
}

.os .os-child-header-ttl {
  width: 271.5px;
  width: 72.4vw;
}

@media screen and (min-width: 640px) {
  .os .os-child-header-ttl {
    width: calc(362px * 0.6);
  }
}

@media screen and (min-width: 767px) {
  .os .os-child-header-ttl {
    width: calc(362px * 0.7);
  }
}

@media screen and (min-width: 980px) {
  .os .os-child-header-ttl {
    width: calc(362px * 0.8);
  }
}

@media screen and (min-width: 1281px) {
  .os .os-child-header-ttl {
    width: 362px;
  }
}

.os .os-child-header-textbox {
  background: #177FA3;
  background: rgba(0, 105, 152, 0.95);
}