.page {
  width: 100%;
  min-height: 100vh;
  background: #0d0d0d;
  padding-bottom: 10%;
}

.page-bg {
  position: absolute;
  width: 100%;
  padding-bottom: 56.25%;
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center;
  z-index: 0;
}

.banner {
  text-align: center;
  color: #fff;
}

.banner .banner-title {
  padding-top: 6.25%;
  line-height: 1;
}

.banner a {
  color: #fff;
}

.year-box {
  margin: 150px auto;
  text-align: center;
}

.year-box .circle-box {
  display: inline-block;
  vertical-align: middle;
  position: relative;
  color: #fff;
}

.year-box .circle-box .year {
  padding: 0 30px;
}

.year-box .circle-box .circle-bg {
  position: absolute;
  width: 100%;
  padding-bottom: 100%;
  top: 50%;
  left: 0;
  transform: translateY(-50%);
  background-image: url(../image/circle.png);
  background-size: 100% 100%;
}

.list {
  position: relative;
  z-index: 99;
  width: 1440px;
  max-width: 90%;
  min-width: 75%;
  margin: 0 auto;
  color: #fff;
  padding: 30px 0;
  overflow: hidden;
  display: flex;
  flex-wrap: wrap;
}

.list::after {
  content: '';
  position: absolute;
  width: 1px;
  height: 100%;
  background-image: linear-gradient(to bottom, transparent, #fff, transparent);
  left: 50%;
  top: 0;
}

.list.pc-list {
  display: flex;
}

.list.mobile-list {
  display: none;
}

.list .item {
  width: 50%;
  float: left;
  margin-bottom: 60px;
  box-sizing: border-box;
}

.list .item.active .year::before {
  content: '';
  position: absolute;
  width: 10px;
  height: 12px;
  background-image: url(../image/triangle_icon.png);
  background-size: 100%;
  left: -15px;
  top: 50%;
  transform: translateY(-50%);
  background-repeat: no-repeat;
  background-position: center;
}

.list .item:nth-child(odd) .item-wrap {
  padding-right: 16%;
}

.list .item:nth-child(even) .item-wrap {
  padding-left: 5%;
}

.list .item-wrap {
  display: flex;
}

.list .item-wrap .label {
  width: 25%;
  white-space: nowrap;
  text-align: right;
  margin-right: 4%;
}

.list .item-wrap .label .year {
  position: relative;
}

.list .item-wrap .desc {
  width: 60%;
  flex: 1;
  line-height: 1.5;
}

@media all and (max-width: 768px) {
  .banner .banner-title {
    padding-top: 40px;
    margin-bottom: 10px;
  }
  .year-box {
    margin: 100px auto;
  }
  .list.pc-list {
    display: none;
  }
  .list.mobile-list {
    display: flex;
  }
  .list::after {
    display: none;
  }
  .list .item {
    width: 100%;
    margin-bottom: 40px;
  }
  .list .item:nth-child(odd) .item-wrap {
    padding-right: 0;
  }
  .list .item:nth-child(even) .item-wrap {
    padding-left: 0;
  }
  .list .item.active .year::before {
    width: 8px;
  }
  .list .item .item-wrap {
    padding-right: 0;
  }
}