.swiper-button-prev:after, .swiper-button-next:after {
  border-color: #ffffff;
  height: 18px;
  width: 18px;
}

.swiper-slide {
  height: auto;
}

#main_slider .swiper-button-prev, #main_slider .swiper-button-next {
  background: rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  height: 60px;
  width: 60px;
}
#main_slider .swiper-pagination .swiper-pagination-bullet {
  height: 10px;
  width: 10px;
  background: #ffffff;
}
#main_slider .swiper-pagination .swiper-pagination-bullet-active {
  opacity: 0.7;
}

#main_slider img, #index_banner img {
  height: auto;
  width: 100%;
}

#_2x2block, #_3x4block {
  display: flex;
  flex-wrap: wrap;
}
#_2x2block .block_item img, #_3x4block .block_item img {
  height: 100%;
  width: 100%;
}

#_2x2block .block_item {
  flex: 0 0 50%;
  height: 50vw;
}
#_2x2block .swiper-button-prev, #_2x2block .swiper-button-next {
  border: 1px solid #ffffff;
  height: 40px;
  bottom: 20px;
  top: auto;
  width: 40px;
}
#_2x2block .swiper-button-prev {
  left: auto;
  right: 70px;
}
#_2x2block .swiper-button-next {
  right: 20px;
}

#_3x4block .block_item {
  flex: 0 0 33.33%;
  height: 33.33vw;
  position: relative;
}
#_3x4block .block_item img, #_3x4block .block_item .block_cover {
  height: 100%;
  width: 100%;
}
#_3x4block .block_item .block_cover {
  align-items: center;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  justify-content: center;
  position: absolute;
  text-align: center;
  transition: all 0.2s linear;
  opacity: 0;
  padding: 10px;
  top: 0;
}
#_3x4block .block_item .block_cover:hover {
  opacity: 1;
}
#_3x4block .block_item .block_cover, #_3x4block .block_item .block_cover a {
  color: #ffffff;
}
#_3x4block .block_item .block_cover h1 {
  font-size: 2.2rem;
}
#_3x4block .block_item .block_cover p {
  font-size: 1.2rem;
}

@media (max-width: 991px) {
  #_3x4block .block_item .block_cover h1 {
    font-size: 1.8rem;
  }
  #_3x4block .block_item .block_cover p {
    font-size: 1.1rem;
  }
}
@media (max-width: 767px) {
  #_3x4block .block_item {
    flex: 0 0 50%;
    height: 50vw;
  }
}
@media (min-width: 576px) {
  .block_down_item {
    order: 4;
  }
}
@media (max-width: 575px) {
  #_2x2block .block_item {
    flex: 0 0 100%;
    height: 100vw;
  }
}
@media (max-width: 450px) {
  #_3x4block .block_item .block_cover h1 {
    font-size: 1.5rem;
  }
  #_3x4block .block_item .block_cover p {
    font-size: 0.9rem;
  }
}