.first-page {
  background-color: #fff;
  position: relative;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
}

.banner-slider-item {
  width: 100vw;
  height: 100vh;
  object-fit: cover;
}
@media (max-width: 768px) {
  .first-page {
    height: auto;
  }
  .banner-slider-item {
    width: 100vw;
    height: 100%;
    object-fit: cover;
  }
}