.container {
  margin: 30px auto 0;
  max-width: 300px;
  width: 100%;
}
.slider .slick-img img {
  height: auto;
  width: 100%;
}

.thumbnail-img {
  opacity: 0.3;
  transition: opacity .3s linear;
}
.thumbnail .slick-current {
  opacity: 1;
}

.thumbnail-img img {
    width: 100%;
}


.thumbnail{
  display: grid;
  grid-template-columns: repeat(3, 1fr); /* 3列×2行=6枚表示 */
  gap: 8px;
}

.thumbnail-img{ opacity: .3; transition: .2s; cursor: pointer; }
.thumbnail-img img{ width:100%; display:block; }