.book-links-block-wrapper {
  display: flex;
  margin: 20px;
}
.book-links-block {
  display: flex;
  gap: 5px;
  width: 100%;
}
.book-links-block__btn {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 1;
  height: 40px;
  border-radius: 20px;
  font-size: 1.3rem;
  font-weight: bold;
  text-align: center;
  text-decoration: none !important;
  color: #fff;
}
.book-links-block__btn.amazon {
  background: #161d26;
  letter-spacing: 0.05em;
}
.book-links-block__btn.rakuten {
  background: #bf0001;
}
.book-links-block__btn.gakken {
  background: #009944;
}

@media screen and (min-width: 769px) {
  .book-links-block {
    max-width: 760px;
    gap: 20px;
  }
  .book-links-block__btn {
    height: 46px;
    border-radius: 23px;
    font-size: 1.6rem;
  }
}