html{
  background:
    url('../images/bk_christmas_top.png') no-repeat top center / 90%,
    url('../images/bk_christmas_bottom.png') no-repeat bottom right / contain,
    linear-gradient(
        to bottom,
        rgba(24,68,15,1),
        rgba(47,127,70,1)
    );
  padding-top: 90px;
}

header{
  position:fixed;
  height: 50px;
  background: linear-gradient(to bottom, rgba(165,128,51,1),rgba(198,163,74,1));
  z-index: 900;
  top: 0;
  width: 100%;
  display: block;
  box-shadow: none;
}

.main-message,
.main-message span{
  color: #fff;
}

.link-lists{
  padding:10px 20px;
  background: rgba(255,255,255,0.5);
}

.header-logo{
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  position: relative;
}

.logo{
  width: 100%;
  max-width: 1200px;
  margin: 10px auto 50px auto;
  border-radius: 30px;
  -webkit-mask-image:
    linear-gradient(to top, transparent, black 10%),
    linear-gradient(to bottom, transparent, black 10%),
    linear-gradient(to left, transparent, black 5%),
    linear-gradient(to right, transparent, black 5%);
  -webkit-mask-composite: intersect;
  mask-composite: intersect;
  mask-image:
    linear-gradient(to top, transparent, black 10%),
    linear-gradient(to bottom, transparent, black 10%),
    linear-gradient(to left, transparent, black 5%),
    linear-gradient(to right, transparent, black 5%);
}

.copyright{
  font-size: 12px;
  position: absolute;
  right: 10px;
  bottom: 10px;
  color: rgba(15,47,9,1)
}

#open-lightbox{
  position: absolute;
  z-index: 1;
  top: 70px;
  left: 60px;
  display: block;
  width: 5vw;
  transition: transform 0.8s ease-in-out; /* スムーズな変化 */
}

@media (max-width:768px) {

  html{
    background:
      url('../images/bk_christmas_top_sp.png') no-repeat top center / 100%,
      url('../images/bk_christmas_bottom_sp.png') no-repeat bottom right / contain,
      linear-gradient(
          to bottom,
          rgba(24,68,15,1),
          rgba(47,127,70,1)
      );
    padding-top: 90px;
  }
  #open-lightbox{
    position: absolute;
    z-index: 1;
  top: 56px;
  left: 12px;
    display: block;
  width: 15vw;
  }
}