.history-block-a {
  --lfw: 650px;
  padding: 140px 0 210px;
  background: url(../images/about/historybg1.jpg) no-repeat center / cover;
}
.aboutB-b {
  margin-top: 0px;
  position: relative;
  width: var(--lfw);
}
.aboutB-b .c-menu {
  position: relative;
  height: 700px;
  margin-left: 360px;
  width: 400px;
  height: 600px;
  margin-left: 300px;
  width: 350px;
  overflow: hidden;
}
.aboutB-b .items-list {
  position: absolute;
  left: -400px;
  top: 0px;
  width: 700px;
  height: 700px;
  border: 1px solid #b5b5b5;
  border-radius: 50%;
  left: -350px;
  width: 600px;
  height: 600px;
}
.aboutB-b .item {
  opacity: 0.5;
  position: absolute;
  width: 600px;
  padding-left: 25px;
  font-size: 18px;
  transition: font-size 1s;
  text-align: left;
  cursor: pointer;
}
.aboutB-b .item a {
  display: block;
  position: relative;
  align-items: center;
  color: #999999;
  transition: color 0.5s;
}
.aboutB-b .item a:before {
  --sw: 16px;
  content: '';
  display: block;
  position: absolute;
  left: 0;
  top: 50%;
  transform: translate(-140%, -50%);
  border-radius: 50%;
  width: var(--sw);
  height: var(--sw);
  background-image: linear-gradient(-34deg, #ed7841 0%, #ebb13c 100%), linear-gradient(#f67524, #f67524);
  background-blend-mode: normal, normal;
  transition: all 0.5s;
}
.aboutB-b .item a:hover {
  color: var(--main-color);
}
.aboutB-b .item:nth-child(4) {
  font-size: 28px;
  margin-top: -4px;
  transition: font-size 0.5s;
  opacity: 1;
}
.aboutB-b .item:nth-child(4):before {
  top: 10px;
}
.aboutB-b .img-box {
  position: absolute;
  left: 0px;
  border-radius: 50%;
  background: rgba(0, 0, 0, 0.1) center / cover;
  top: 50px;
  width: 500px;
  height: 500px;
  opacity: 1;
  transition: opacity 2s;
}
.aboutB-b .item:nth-child(2),
.aboutB-b .item:nth-child(3),
.aboutB-b .item:nth-child(11),
.aboutB-b .item:nth-child(12) {
  opacity: 0.7;
}
.aboutB-c {
  width: calc(90% - var(--lfw));
  overflow: hidden;
  position: relative;
}
.aboutB-c .t {
  font-size: 60px;
  font-weight: bold;
  line-height: 0.8em;
  color: #333333;
}
.aboutB-c .t .t-t {
  display: inline-block;
  margin-left: 0.6em;
  transform: translateY(-10%);
  font-size: 20px;
  line-height: 1.4em;
  display: none;
}
.aboutB-c .c {
  margin-top: 30px;
  height: 260px;
  padding-right: 5%;
  overflow-y: scroll;
  text-align: justify;
  font-size: 18px;
  color: #666666;
  line-height: 1.77em;
  /*滚动条的轨道*/
  /*滚动条的滑块按钮*/
}
.aboutB-c .c::-webkit-scrollbar {
  background-color: transparent;
  width: 3px;
  height: 3px;
}
.aboutB-c .c::-webkit-scrollbar-track {
 /* background-color: #b3b3b3;*/ background-color: transparent;
  border-radius: 10px;
}
.aboutB-c .c::-webkit-scrollbar-thumb {
  border-radius: 10px;
  background-color: var(--main-color);
}
.aboutB-c .btn-box {
  padding-top: 60px;
}
.aboutB-c .btn {
  --sw: 60px; border-radius: 5px;
}
.aboutB-c .btn .self-svg {
  --size: 40%;
  --fill: var(--main-color);
  border: solid 1px var(--main-color);
  border-radius: 5px;
  width: var(--sw);
  height: var(--sw);
  background: transparent;
  transition: background 0.3s;
}
.aboutB-c .btn .self-svg svg {
  margin-left: -4%;
}
.aboutB-c .btn:hover {
  background-image: linear-gradient(-34deg, #ed7841 0%, #ebb13c 100%), linear-gradient(#f67524, #f67524);
  background-blend-mode: normal, normal;
}
.aboutB-c .btn:hover .self-svg {
  --fill: #ffffff;
}
.aboutB-c .btn.prev svg {
  transform: rotate(180deg);
}
.aboutB-c .btn.next {
  margin-left: calc(var(--sw)*0.33);
}
@media (max-width: 1660px) {
  .history-block-a {
    padding: 120px 0 180px;
  }
  .aboutB-c {
    width: calc(95% - var(--lfw));
  }
  .aboutB-c .c {
    line-height: 1.6em;
  }
  .aboutB-c .btn-box {
    padding-top: 50px;
  }
}
@media (max-width: 1550px) {
  .history-block-a {
    padding: 110px 0 150px;
  }
  .aboutB-c {
    width: calc(98% - var(--lfw));
  }
  .aboutB-c .c {
    height: 220px;
  }
  .aboutB-c .btn-box {
    padding-top: 40px;
  }
}
@media (max-width: 1400px) {
  .history-block-a {
    padding: 100px 0 100px;
  }
}
@media (max-width: 960px) {
  .history-block-a .aboutB-a{display: block;}
  .aboutB-b{width: 100%;}
  .aboutB-c{width: calc(100% - 0px);margin-top: 5%;}
}
@media (max-width: 640px) {
  .aboutB-b{zoom: 0.8;}
  .aboutB-c .t{font-size: 50px;}
  .aboutB-c .c{font-size: 16px; height: 200px;}
  .aboutB-c .btn-box{padding-top: 4%;}
  
}

@media (max-width: 520px) {
  .history-block-a{padding-top: 8%;padding-bottom: 8%;}
  .aboutB-b{zoom: 0.7;}
  .aboutB-c .t{font-size: 40px;}
  .aboutB-c .c{margin-top: 4%;font-size: 14px;}
}

@media (max-width: 480px) {
  .aboutB-b{zoom: 0.6;}
}
@media (max-width: 420px) {
  .aboutB-b{zoom: 0.55;}
}