.btn--gradation {
  color: #FFF;
  background: -webkit-gradient(linear, left top, left bottom, from(#78b3fb), to(#539cf7));
  background: linear-gradient(to bottom, rgba(120, 179, 251, 0.6), rgba(83, 156, 247, 0.6));
  background-color: #78b3fb;
  -moz-transition: background, 0.6s, liner;
  -o-transition: background, 0.6s, liner;
  -webkit-transition: background, 0.6s, liner;
  transition: background, 0.6s, liner;
  -moz-transition: background-color, 0.6s, liner;
  -o-transition: background-color, 0.6s, liner;
  -webkit-transition: background-color, 0.6s, liner;
  transition: background-color, 0.6s, liner;
}
.btn--gradation:hover {
  color: #FFF;
  background: -webkit-gradient(linear, left top, left bottom, from(#529bf7), to(#478ddf));
  background: linear-gradient(to bottom, rgba(82, 155, 247, 0.6), rgba(71, 141, 223, 0.6));
  background-color: #529bf7;
}

.contents_index--menu .subBox__inner.greeting a::after {
  background: url(../image/about/bg01.jpg);
}
.contents_index--menu .subBox__inner.outline a::after {
  background: url(../image/about/bg02.jpg);
}
.contents_index--menu .subBox__inner.disclosure a::after {
  background: url(../image/about/bg03.jpg);
}
.contents_index--menu .subBox__inner.iso a::after {
  background: url(../image/about/bg04.jpg);
}
.contents_index--menu .subBox__inner.download a::after {
  background: url(../image/about/bg05.jpg);
}