.header .banner {
  background: url(../images/about_关于白山.png) center;
}
.main .introduction {
  max-width: 1440px;
  padding: 0 120px;
  margin: 80px auto 40px auto;
  background: #fff;
}
.main .introduction .title {
  font-size: 32px;
  line-height: 32px;
  text-align: center;
  font-weight: 500;
}
.main .introduction .desc {
  margin-top: 40px;
  font-size: 14px;
  color: #6B7586;
  font-weight: 400;
  line-height: 22px;
}
.main .introduction .desc p:last-child {
  margin-bottom: 80px;
}
@media only screen and (max-width: 750px) {
  .main .introduction {
    padding: 0 24px;
  }
  .main .introduction .title {
    font-size: 18px;
  }
}
.main .time-line-wrapper {
  background-color: #F5F6FA;
  overflow: hidden;
  padding: 80px 0;
}
.main .time-line-wrapper .title {
  font-size: 32px;
  text-align: center;
  font-weight: 500;
}
.main .time-line-wrapper .time-line-container {
  margin: 42px auto 0;
  max-width: 1200px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  position: relative;
}
.main .time-line-wrapper .time-line-container .time-line-year-container {
  display: flex;
  align-items: flex-start;
  position: relative;
  transform: translateX(300px);
  margin-left: 152px;
}
.main .time-line-wrapper .time-line-container .time-line-year-container:not(.main .time-line-wrapper .time-line-container .time-line-year-container:last-child) {
  padding-bottom: 38px;
}
.main .time-line-wrapper .time-line-container .time-line-year-container:not(.main .time-line-wrapper .time-line-container .time-line-year-container:last-child)::before {
  position: absolute;
  left: 0;
  top: 0;
  content: '';
  width: 2px;
  height: 100%;
  background-color: #EBEDF4;
  margin-top: 10px;
}
.main .time-line-wrapper .time-line-container .time-line-year-container .item-list {
  padding-left: 37px;
}
.main .time-line-wrapper .time-line-container .time-line-year-container .item-list .year-container {
  display: flex;
  align-items: center;
  justify-items: center;
  position: absolute;
  margin-left: -152px;
}
.main .time-line-wrapper .time-line-container .time-line-year-container .item-list .year-container .text {
  flex: 0 0 110px;
  font-size: 20px;
  font-family: PingFangSC-Regular, PingFang SC;
  font-weight: 400;
  color: #31394D;
  line-height: 20px;
  padding-right: 37px;
}
.main .time-line-wrapper .time-line-container .time-line-year-container .item-list .year-container .icon {
  flex: 0 0 12px;
  height: 12px;
  position: relative;
  z-index: 9;
}
.main .time-line-wrapper .time-line-container .time-line-year-container .item-list .item-container {
  display: flex;
  align-items: center;
  max-width: 800px;
}
.main .time-line-wrapper .time-line-container .time-line-year-container .item-list .item-container + .item-container {
  margin-top: 18px;
}
.main .time-line-wrapper .time-line-container .time-line-year-container .item-list .item-container .month {
  font-size: 18px;
  font-family: ArialMT;
  font-weight: 400;
  color: #31394D;
  line-height: 18px;
  min-width: 42px;
  text-align: right;
}
.main .time-line-wrapper .time-line-container .time-line-year-container .item-list .item-container .content {
  margin-left: 20px;
  font-size: 14px;
  font-family: PingFangSC-Regular, PingFang SC;
  font-weight: 400;
  color: #6B7586;
  line-height: 20px;
}
@media only screen and (max-width: 750px) {
  .main .time-line-wrapper .title {
    font-size: 18px;
  }
  .main .time-line-wrapper .time-line-container {
    padding: 0 27px 0 24px;
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container {
    margin-left: 0;
    transform: translateX(0);
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container:not(.main .time-line-wrapper .time-line-container .time-line-year-container:last-child) {
    padding-bottom: 24px;
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container .item-list {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    padding-left: 15px;
    margin-left: 0;
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container .item-list .year-container {
    position: sticky;
    flex-direction: row-reverse;
    margin-left: -3px;
    padding-bottom: 16px;
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container .item-list .year-container + .item-container {
    margin-top: 10px;
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container .item-list .year-container .text {
    margin-left: 10px;
    font-size: 16px;
    font-family: PingFangSC-Regular, PingFang SC;
    font-weight: 400;
    color: #31394D;
    line-height: 16px;
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container .item-list .item-container {
    display: flex;
    align-items: flex-start;
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container .item-list .item-container .month {
    font-size: 14px;
    font-family: PingFangSC-Regular, PingFang SC;
    font-weight: 400;
    color: #31394D;
    line-height: 20px;
    white-space: nowrap;
  }
  .main .time-line-wrapper .time-line-container .time-line-year-container .item-list .item-container .content {
    margin-left: 10px;
    font-size: 14px;
    font-family: PingFangSC-Regular, PingFang SC;
    font-weight: 400;
    color: #6B7586;
    line-height: 20px;
  }
}