/* 横の案アンダーライン */
.ground-nav a {
  position: relative;
  text-decoration: none;
  color: #ffffff;
  transition: 0.3s;
}
.ground-nav a:hover {
  color: #894b33;
}
.ground-nav a::before {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 0;
  height: 3px;
  background: #ffffff;
  transition: 0.5s;
}
.ground-nav a:hover::before {
  width: 100%;
}
/* 色が反転 */