<div class="mask">
  <div class="swiper-container">
    <div class="swiper-wrapper">
      <div class="swiper-slide">Slide 1</div>
      <div class="swiper-slide">Slide 2</div>
      <div class="swiper-slide">Slide 3</div>
      <div class="swiper-slide">Slide 4</div>
      <div class="swiper-slide">Slide 5</div>
      <div class="swiper-slide">Slide 6</div>
      <div class="swiper-slide">Slide 7</div>
      <div class="swiper-slide">Slide 8</div>
      <div class="swiper-slide">Slide 9</div>
      <div class="swiper-slide">Slide 10</div>
      <div class="swiper-slide">Slide 11</div>
      <div class="swiper-slide">Slide 12</div>
      <div class="swiper-slide">Slide 13</div>
      <div class="swiper-slide">Slide 14</div>
      <div class="swiper-slide">Slide 15</div>
      <div class="swiper-slide">Slide 16</div>
      <div class="swiper-slide">Slide 17</div>
      <div class="swiper-slide">Slide 18</div>
      <div class="swiper-slide">Slide 19</div>
      <div class="swiper-slide">Slide 20</div>
    </div>
    <!-- Add Pagination -->
    <div class="swiper-pagination"></div>
  </div>
</div>

    html, body {
      position: relative;
      height: 100%;
    overflow: hidden;
    }
    body {
      background: #eee;
      font-family: Helvetica Neue, Helvetica, Arial, sans-serif;
      font-size: 14px;
      color:#000;
      margin: 0;
      padding: 0;

    }
    .swiper-container {
      width: 55%;
      height: 100%;
      margin-left: auto;
      margin-right: auto;
    }
    .swiper-slide {
      text-align: center;
      font-size: 18px;
      background: #fff;
      height: 100%;
/*    opacity: 0.3; */

      /* Center slide text vertically */
      display: -webkit-box;
      display: -ms-flexbox;
      display: -webkit-flex;
      display: flex;
      -webkit-box-pack: center;
      -ms-flex-pack: center;
      -webkit-justify-content: center;
      justify-content: center;
      -webkit-box-align: center;
      -ms-flex-align: center;
      -webkit-align-items: center;
      align-items: center;
     transition: .3s all;
     transform: scale(0.8);
    }

.swiper-slide-prev,
.swiper-slide-next,
.swiper-slide-duplicate-prev,
.swiper-slide-duplicate-next {
  transform: scale(0.9)
}

.swiper-slide-active,
.swiper-slide-duplicate-active {
  transform: scale(1);
  opacity: 1;
}

.mask {
  width: 100%;
  height: 100%;
  -webkit-mask: linear-gradient(
    to right,
    rgba(0, 0, 0, 0) 0%,
    rgba(0, 0, 0, 1) 20%,
    rgba(0, 0, 0, 1) 80%,
    rgba(0, 0, 0, 0) 100%
  );
}

var swiper = new Swiper(".swiper-container", {
  slidesPerView: 3,
  loop: true,
  centeredSlides: true,
  spaceBetween: 30,
  pagination: {
    el: ".swiper-pagination",
    clickable: true
  }
});