.slider {
  position: relative;
  width: calc(540 / 768 * 100%);
  margin: auto;
  overflow: hidden;
}

.slider-wrap {
  display: flex;
  transition: transform 0.4s ease;
}

.slide {
  width: 100%;
  flex-shrink: 0;
  text-align: center;
}

/* ボタン */
.slider-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  z-index: 999;
}

.slider-btn img {
  width: 100%;
  height: auto;
}

.slider-btn.prev {
  left: 7%;
}

.slider-btn.next {
  right: 7%;
}

  .slider-area .slider-btn.prev {
    width: 20px;
  }
  .slider-area .slider-btn.next {
    width: 20px;
  }