/* from inline style block */
#btSns {
  display: none;
}
@media only screen and (max-width: 640px) {
  #btSns {
    display: block;
    width: var(--size-100);
    height: 80px;
    position: absolute;
    top: 0;
    left: 0;
    z-index: +1;
    font-size: 27px;
    text-align: center;
  }
  #btSns .fa {
    margin-right: 0;
    line-height: 80px;
  }
}

/* for inline style attributes */
#mainImage {
  background-image: url('../imgs/top/bg_main.jpg');
  background-position: center center;
  background-size: cover;
}

#lesson .inr:nth-of-type(1) .image {
  background-image: url('../imgs/top/bg_group.jpg');
}

#lesson .inr:nth-of-type(2) .image {
  background-image: url('../imgs/top/bg_private.jpg');
}

#instagram {
  background-image: url('../imgs/top/bg_sub.jpg');
  background-position: center center;
  background-size: cover;
  height: 310px;
}

.ownerimage {
  background-image: url('../imgs/top/bg_owner.jpg');
  background-position: center center;
  background-size: cover;
}

iframe {
    border: 0;
}