.column-flex{
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

.banner .title{
  height:84px;
  font-size:60px;
  font-family:PingFangSC-Semibold,PingFang SC;
  font-weight:600;
  color:rgba(255,255,255,1);
  line-height:84px;
  letter-spacing:1px;
  margin-top: 20px;
}

.banner .title-desc{
  height:33px;
  font-size:24px;
  font-family:PingFangSC-Regular,PingFang SC;
  font-weight:400;
  color:rgba(255,255,255,1);
  line-height:33px;
  margin-top: 8px;
}

.banner .download-btn{
  width:240px;
  height:56px;
  text-align: center;
  background:rgba(255,255,255,1);
  border-radius:30px;
  font-size:18px;
  font-family:PingFangSC-Medium,PingFang SC;
  font-weight:500;
  color:rgba(23,149,255,1);
  line-height:56px;
  margin-top: 32px;
  cursor: pointer;
  transition: transform .2s;
}

.download-btn .download-icon,.download-btn2 .download-icon {
  width: 24px;
  height: 24px;
  display: inline-block;
  background-repeat: no-repeat;
  background-position: center center;
  background-size: contain;
  position: relative;
  top: 5px;
}

.download-btn .blue{
  background-image: url(../img/download/download-blue_cc9f630a3f.png);
}

.download-btn2 .white{
  background-image: url(../img/download/download-white_c07e83873d.png);
}

.banner .download-btn:hover{
  transform: scale(1.1);
}

.banner .download-tip{
  font-size:14px;
  font-family:PingFangSC-Regular,PingFang SC;
  font-weight:400;
  color:rgba(255,255,255,1);
  line-height:20px;
  margin-top: 8px;
}

.content-wrap{
  width: 100%;
}

.section-1{
  width: 100%;
  height: 524px;
  background: #fff;
  position: relative;
  opacity: 0;
  z-index: 1;
}

.section-1 .contrast-demo{
  width: 846px;
  height: 474px;
  position: relative;
  top: -145px;
}
.demo-1080p, .demo-normal{
  position: absolute;
  left: 0;
  right: 0;
  height: 100%;
  background-size: cover;
  background-repeat: no-repeat;
  overflow: hidden;
}

.demo-text{
  color: #fff;
  text-align: center;
  width:120px;
  height:32px;
  line-height: 32px;
  background:rgba(61,77,105,0.1);
  border-radius:4px;
  border:2px solid rgba(255,255,255,1);
  position: absolute;
  top: 16px;
}

.demo-1080p{
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/1080p-demo_7a05e43b1d.png);
  right: 50%;
}

.demo-1080p .demo-text{
  left: 16px;
}

.demo-normal .demo-text{
  right: 16px;
}

.demo-normal{
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/normal-demo_04c528118e.png);
}

.slider{
  height: 100%;
  position: absolute;
  width: 46px;
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/slider_77d18f6a8c.png);
  background-size: cover;
  background-position: center center;
  left: 400px;
  cursor: col-resize;
}


.section-1 .advantage{
  color: #3D4D69;
  font-size: 24px;
  position: absolute;
  bottom: 112px;
}

.section-1 .advantage-desc{
  font-size: 16px;
  color: #3D4D69;
  position: absolute;
  bottom: 78px;
}

.section-2{
  width: 100%;
  background: #F1F3F5;
}

.section-2 .key-back{
  width: 100%;
  height: 115px;
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/keywords_0bcff2af98.png);
  background-repeat: no-repeat;
  background-size: cover;
  background-position: center center;
}
.section-2 .points{
  margin: 0 auto;
  width: 990px;
  padding-top: 40px;
  padding-bottom: 100px;
  opacity: 0;
}

.points .row-flex{
  width: 990px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 30px;
}

.row-flex .flex-item{
  width: 190px;
  height: 190px;
  background-repeat: no-repeat;
  background-position: center center;
  background-size: 80%;
  position: relative;
}

.row-flex .flex-item:hover{
  transition: transform .2s;
  transform: scale(1.2);
}

.flex-item .text{
  position: absolute;
  bottom: 0;
  color: #091D2D;
  font-size: 18px;
  width: 100%;
  text-align: center;
}

.recorder {
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/recorder_0ce4ae11c8.png);
}
.file {
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/file_39b6aea378.png);
}
.screen {
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/screen_a72faa169b.png);
}
.airplay {
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/airplay_c116a7d147.png);
}
.meeting {
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/meeting_e10b155bfe.png);
}
.live {
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/live_8fd4105cf5.png);
}
.switch {
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/switch_1651bdc702.png);
}
.combine {
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/download/combine_4f0434112d.png);
}

.section-3{
  width: 100%;
  background: #fff;
  opacity: 0;
}

.title-ch{
  font-size: 24px;
  color: #3D4D69;
  margin-top: 60px;
}

.section-3 .title-desc{
  font-size: 16px;
  color: #3D4D69;
  margin-bottom: 48px;
  margin-top: 16px;
}

.section-3 .video-slider{
  width: 100%;
  position: relative;
  overflow: hidden;
  cursor: pointer;
}
.video-slider .video-list{
  width: 166.7%;
  display: flex;
  justify-content: space-between;
  position: relative;
  left: 0;
  transition: left .5s;
}
.video-slider .video-item{
  width: 20%;
  height: auto;
  margin: 0 10px;
  position: relative;
}

.video-item .video-poster{
  width: 100%;
  height: auto;
}

.video-item .text{
  position: absolute;
  width: 100%;
  bottom: 15px;
  font-size:24px;
  font-family:PingFangSC-Medium,PingFang SC;
  font-weight:500;
  color: #fff;
  text-align: center;
}

.section-3 .video-layer{
  position: fixed;
  top: 0;
  bottom: 0;
  right: 0;
  left: 0;
  background: rgba(0,0,0,.7);
  display: none;
  z-index: 10;
}

.video-layer .video-wrap{
  width: 960px;
  height: 540px;
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  margin: auto;
}

.video-wrap .video-playing{
  width: 100%;
}

.video-wrap .close-btn{
  position: absolute;
  width: 32px;
  height: 32px;
  top: -40px;
  right: 0;
  background-image: url(/homepage/asset/frontend/doubleTeacher/img/close_4bcbe04a7c.png);
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center center;
  cursor: pointer;
}

.video-slider .dot-list{
  margin: 0 auto;
  display: flex;
  justify-content: center;
  align-items: center;
  margin-top: 48px;
  margin-bottom: 58px;
}

.dot-list .dot-line{
  display: inline-block;
  width:64px;
  height:8px;
  background:rgba(223,223,226,1);
  border-radius:4px;
  margin: 0 16px;
  transition: width .5s;
}

.dot-list .active{
  width:120px;
  height:8px;
  background:linear-gradient(180deg,rgba(51,199,255,1) 0%,rgba(23,149,255,1) 100%);
  box-shadow:0px 10px 20px 0px rgba(23,149,255,0.2);
  border-radius:4px;
}

.section-4{
  width: 100%;
  opacity: 0;
}

.section-4 .content{
  width: 1200px;
  margin: 45px auto;
  position: relative;
}

.content .left-panel{
  width: 500px;
  height: 375px;
  justify-content: space-between;
}

.left-panel .item{
  width: 100%;
  height:100px;
  box-sizing: border-box;
  background:rgba(255,255,255,1);
  box-shadow:0px 10px 40px 0px rgba(0,0,0,0.1);
  border-radius:8px;
  padding: 14px 17px;
  transition: transform .5s;
  position: relative;
  cursor: pointer;
}

.left-panel .item .item-title{
  position: absolute;
  font-size:16px;
  font-family:PingFangSC-Regular,PingFang SC;
  font-weight:400;
  color:rgba(61,77,105,1);
  height: 22px;
  display: inline-block;
  line-height:22px;
  text-shadow:0px 10px 40px rgba(0,0,0,0.1);
}

.left-panel .item .item-text{
  font-size:14px;
  font-family:PingFangSC-Light,PingFang SC;
  font-weight:300;
  color:rgba(61,77,105,1);
  line-height:20px;
  text-shadow:0px 10px 40px rgba(0,0,0,0.1);
  margin-top: 10px;
  position: absolute;
  left: 17px;
  right: 17px;
  bottom: 14px;
}
.right-panel{
  position: absolute;
  right: 0;
  top: 0;
  height: 375px;
  width: 665px;
  box-shadow:0px 10px 40px 0px rgba(0,0,0,0.1);
  border-radius:8px;
  overflow: hidden;
}
.right-panel .item-img{
  width: 665px;
  height: 375px;
  display: none;
}

.right-panel .active{
  display: block;
}


.section-4  .left-panel .active{
  transform: scale(1.1);
}
.left-panel .active .item-title::after{
  content: '';
  display: block;
  width: 100%;
  height: 4px;
  background:linear-gradient(180deg,rgba(51,199,255,1) 0%,rgba(23,149,255,1) 100%);
  box-shadow:0px 10px 20px 0px rgba(23,149,255,0.2);
  border-radius:2px;
}

.item-title::after{
  content: '';
  display: block;
  width: 0;
  height: 4px;
  background:linear-gradient(180deg,rgba(51,199,255,1) 0%,rgba(23,149,255,1) 100%);
  box-shadow:0px 10px 20px 0px rgba(23,149,255,0.2);
  border-radius:2px;
  transition: width .2s;
}

.bottom-panel{
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin: 90px 0;
  opacity: 0;
}

.download-animate{
  opacity: 0;
}

.download-btn2{
  width:240px;
  height:56px;
  background:linear-gradient(180deg,rgba(51,199,255,1) 0%,rgba(23,149,255,1) 100%);
  border-radius:30px;
  color: #fff !important;
  font-size:18px;
  font-family:PingFangSC-Medium,PingFang SC;
  font-weight:500;
  text-align: center;
  line-height: 56px;
  cursor: pointer;
  transition: transform .2s;
}

.download-btn2:hover{
  transform: scale(1.1);
}

.download-tip2{
  margin-top: 8px;
  font-size:14px;
  font-family:PingFangSC-Regular,PingFang SC;
  font-weight:400;
  color:rgba(189,198,207,1);
}

/* 加载动画 */
.load-animate{
  opacity: 1 !important;
  position: relative;
  animation-fill-mode:forwards;
  -webkit-animation-fill-mode:forwards; /* Safari 和 Chrome */
  animation: fade-up 1s;
}

@keyframes fade-up{
  from {
    top: 50px;
    opacity: 0;
  }
  to {
    top: 0;
    opacity: 1;
  }
}

@-webkit-keyframes fade-up{
  from {
    top: 50px;
    opacity: 0;
  }
  to {
    top: 0;
    opacity: 1;
  }
}

.footer .anniversary-stick{
	display: flex !important;
}