.scrolldown {
  bottom: 300px;
}

.bg {
  position: relative;
  width: 100%;
  height: calc(100vh - 200px);
  overflow: hidden;
}
.bg .pic {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  background-size: cover;
  background-position: center;
  -moz-transform: scale(1.1) perspective(500px) translateZ(0px);
  -ms-transform: scale(1.1) perspective(500px) translateZ(0px);
  -webkit-transform: scale(1.1) perspective(500px) translateZ(0px);
  transform: scale(1.1) perspective(500px) translateZ(0px);
  -moz-transition: -moz-transform 0s cubic-bezier(0.25, 0.25, 0.75, 0.75);
  -o-transition: -o-transform 0s cubic-bezier(0.25, 0.25, 0.75, 0.75);
  -webkit-transition: -webkit-transform 0s cubic-bezier(0.25, 0.25, 0.75, 0.75);
  transition: transform 0s cubic-bezier(0.25, 0.25, 0.75, 0.75);
}
.bg .pic.move-img {
  -moz-transform: scale(1.1) perspective(500px) translateZ(-50px);
  -ms-transform: scale(1.1) perspective(500px) translateZ(-50px);
  -webkit-transform: scale(1.1) perspective(500px) translateZ(-50px);
  transform: scale(1.1) perspective(500px) translateZ(-50px);
  -moz-transition-duration: 5s;
  -o-transition-duration: 5s;
  -webkit-transition-duration: 5s;
  transition-duration: 5s;
}
.bg .top-mask {
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.1);
  position: relative;
}

.top-title {
  position: absolute;
  left: 20%;
  top: 40%;
  color: #fff;
  z-index: 10;
}
.top-title-big, .top-title-big2 {
  font-size: 40px;
}

.level {
  padding-top: 100px 0;
}
.level .box {
  display: flex;
  padding: 100px 0;
}
.level .concept-pic {
  position: relative;
  width: 80%;
  overflow: hidden;
}
.level .concept-pic img {
  height: 110%;
  position: relative;
  -moz-transform: scale(1, 1);
  -ms-transform: scale(1, 1);
  -webkit-transform: scale(1, 1);
  transform: scale(1, 1);
  -moz-transition: all 1s cubic-bezier(0.165, 0.84, 0.44, 1);
  -o-transition: all 1s cubic-bezier(0.165, 0.84, 0.44, 1);
  -webkit-transition: all 1s cubic-bezier(0.165, 0.84, 0.44, 1);
  transition: all 1s cubic-bezier(0.165, 0.84, 0.44, 1);
}
.level .concept {
  width: 80%;
}
.level .square {
  position: absolute;
  top: 10%;
  width: 400px;
  height: 300px;
  border: 3px solid #ddd;
  -moz-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -o-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -webkit-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
}
.level .concept-text {
  position: relative;
  top: 80%;
  max-width: 300px;
  min-width: 300px;
  margin-bottom: 20px;
  border: 1px solid #666;
  -moz-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -o-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -webkit-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  padding: 80px 50px;
  box-sizing: border-box;
  box-shadow: 0 0 30px rgba(0, 0, 0, 0.5);
}
.level .title-name {
  font-size: 20px;
  margin-bottom: 20px;
  overflow: hidden;
}
.level .title-name span {
  display: inline-block;
}
.level .title-big {
  margin-bottom: 20px;
  color: #666;
  position: absolute;
  top: -30px;
  text-align: left;
  width: 220px;
  -moz-transform: rotate(90deg);
  -ms-transform: rotate(90deg);
  -webkit-transform: rotate(90deg);
  transform: rotate(90deg);
}
.level .view {
  font-size: 10px;
  letter-spacing: 0.2em;
  -moz-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -o-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -webkit-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -moz-transition-delay: 0.28s;
  -o-transition-delay: 0.28s;
  -webkit-transition-delay: 0.28s;
  transition-delay: 0.28s;
  color: #bdbdbd;
}
.level .concept-line {
  width: 250px;
  height: 12px;
  background: #666;
  position: absolute;
  top: 190px;
  -moz-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -o-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  -webkit-transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
  transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
}
.level a:hover .concept-text {
  border: 1px solid #ccc;
  box-shadow: 0 0 30px rgba(0, 0, 0, 0.8);
}
.level a:hover .square {
  border: 3px solid #ccc;
}
.level a:hover .title-big {
  color: #ccc;
}
.level a:hover .concept-line {
  background: #ccc;
}
.level a:hover .view {
  letter-spacing: 0.5em;
}
.level a:hover .view:nth-child(odd):before {
  background-color: #bdbdbd;
  padding-left: 30px;
  margin-right: 20px;
}
.level a:hover .view:nth-child(odd):after {
  background-color: #bdbdbd;
  padding-left: 30px;
  margin-left: 20px;
}
.level a:hover .concept-pic img {
  -moz-transform: scale(1.1, 1.1);
  -ms-transform: scale(1.1, 1.1);
  -webkit-transform: scale(1.1, 1.1);
  transform: scale(1.1, 1.1);
}

.level a:nth-child(odd) .square {
  margin-left: 100px;
}
.level a:nth-child(odd) .title-big {
  left: 250px;
}
.level a:nth-child(odd) .concept-text {
  margin-left: 200px;
}
.level a:nth-child(odd) .concept-line {
  right: 80px;
}
.level a:nth-child(odd) .view:before {
  content: "";
  display: inline-block;
  background-color: #bdbdbd;
  padding-left: 130px;
  padding-top: 1px;
  margin-right: 20px;
  position: relative;
  top: -10px;
  -moz-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
  -o-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
  -webkit-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
  transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
}
.level a:nth-child(odd):hover .concept-line {
  right: -30px;
}

.level a:nth-child(even) .box {
  flex-direction: row-reverse;
}
.level a:nth-child(even) .square {
  text-align: right;
  margin-right: 100px;
}
.level a:nth-child(even) .title-big {
  right: 250px;
}
.level a:nth-child(even) .concept-text {
  float: right;
  text-align: right;
  margin-right: 200px;
}
.level a:nth-child(even) .concept-line {
  left: 80px;
}
.level a:nth-child(even) .view:after {
  content: "";
  display: inline-block;
  background-color: #bdbdbd;
  padding-left: 130px;
  padding-top: 1px;
  margin-left: 20px;
  position: relative;
  top: -10px;
  -moz-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
  -o-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
  -webkit-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
  transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
}
.level a:nth-child(even):hover .concept-line {
  left: -30px;
}

.move1 {
  opacity: 0;
  -moz-transform: translateY(100px);
  -ms-transform: translateY(100px);
  -webkit-transform: translateY(100px);
  transform: translateY(100px);
}

.move1 {
  -moz-transition: opacity 0.8s, -moz-transform 0.8s;
  -o-transition: opacity 0.8s, -o-transform 0.8s;
  -webkit-transition: opacity 0.8s, -webkit-transform 0.8s;
  transition: opacity 0.8s, transform 0.8s;
}
.move1.show {
  width: 80%;
  opacity: 1;
  -moz-transform: translate(0px, 0px);
  -ms-transform: translate(0px, 0px);
  -webkit-transform: translate(0px, 0px);
  transform: translate(0px, 0px);
}

.move2 {
  opacity: 0;
  -moz-transform: translateY(-80px);
  -ms-transform: translateY(-80px);
  -webkit-transform: translateY(-80px);
  transform: translateY(-80px);
}

.move2 {
  -moz-transition: opacity 1.5s, -moz-transform 1.2s;
  -o-transition: opacity 1.5s, -o-transform 1.2s;
  -webkit-transition: opacity 1.5s, -webkit-transform 1.2s;
  transition: opacity 1.5s, transform 1.2s;
  -moz-transition-delay: 3s;
  -o-transition-delay: 3s;
  -webkit-transition-delay: 3s;
  transition-delay: 3s;
}
.move2.show {
  opacity: 1;
  -moz-transform: translate(0px, 0px);
  -ms-transform: translate(0px, 0px);
  -webkit-transform: translate(0px, 0px);
  transform: translate(0px, 0px);
}

.move3 {
  -moz-transform: translateY(50px);
  -ms-transform: translateY(50px);
  -webkit-transform: translateY(50px);
  transform: translateY(50px);
}

.move3 {
  -moz-transition: -moz-transform 0.5s;
  -o-transition: -o-transform 0.5s;
  -webkit-transition: -webkit-transform 0.5s;
  transition: transform 0.5s;
}
.move3.show {
  -moz-transform: translateY(0px);
  -ms-transform: translateY(0px);
  -webkit-transform: translateY(0px);
  transform: translateY(0px);
}

@media screen and (max-width: 1500px) {
  .level .concept {
    width: 70%;
  }

  .level a:nth-child(odd) .concept-text {
    margin-left: 100px;
  }

  .level a:nth-child(even) .concept-text {
    margin-right: 100px;
  }
}
@media screen and (max-width: 1350px) {
  .level .concept {
    width: 60%;
  }
}
@media screen and (max-width: 1200px) {
  .level a:nth-child(odd) .concept-text {
    margin-left: 50px;
  }

  .level a:nth-child(even) .concept-text {
    margin-right: 50px;
  }
}
@media screen and (max-width: 1100px) {
  .level .box {
    padding-top: 100px;
  }
  .level .concept {
    margin-top: 80px;
  }
  .level .concept-pic {
    width: 68%;
  }
  .level .concept-pic img {
    height: unset;
    width: 100%;
  }
  .level .concept-text {
    position: relative;
    padding: 50px 50px;
  }
  .level .concept-line {
    height: 8px;
    top: 140px;
  }

  .level a:nth-child(odd) .view:before {
    margin-right: 20px;
  }
  .level a:nth-child(odd) .title-big {
    left: 230px;
  }

  .level a:nth-child(even) .view:after {
    margin-left: 20px;
  }
  .level a:nth-child(even) .title-big {
    right: 230px;
  }

  .move2 {
    -moz-transition-delay: 0s;
    -o-transition-delay: 0s;
    -webkit-transition-delay: 0s;
    transition-delay: 0s;
  }

  .move3 {
    -moz-transition: -moz-transform 0.3s;
    -o-transition: -o-transform 0.3s;
    -webkit-transition: -webkit-transform 0.3s;
    transition: transform 0.3s;
  }
}
@media screen and (max-width: 900px) {
  .level a:nth-child(odd) .view:before {
    padding-left: 100px;
  }
  .level a:nth-child(odd) .title-big {
    left: 150px;
  }
  .level a:nth-child(odd) .concept-text {
    margin-left: 30px;
    margin-top: 20px;
  }
  .level a:nth-child(odd) .concept-line {
    right: 60px;
  }

  .level a:nth-child(even) .view:after {
    padding-left: 100px;
  }
  .level a:nth-child(even) .title-big {
    right: 150px;
  }
  .level a:nth-child(even) .concept-text {
    margin-right: 30px;
  }
  .level a:nth-child(even) .concept-line {
    left: 60px;
  }

  .level .concept-text {
    padding: 50px 30px;
    max-width: 230px;
    min-width: 230px;
  }
  .level .concept-line {
    width: 180px;
  }
  .level a:hover .view {
    letter-spacing: 0.2em;
  }
  .level a:hover .view:nth-child(even):before {
    padding-left: 180px;
  }
  .level a:hover .view:nth-child(even):after {
    padding-left: 180px;
  }
  .level a:hover .concept-pic img {
    -moz-transform: scale(1, 1);
    -ms-transform: scale(1, 1);
    -webkit-transform: scale(1, 1);
    transform: scale(1, 1);
  }
  .level .title-big {
    font-size: 28px;
  }
}
@media screen and (max-width: 720px) {
  .level .box {
    display: block;
    padding-top: 50px;
    padding-bottom: 50px;
  }
  .level .concept {
    margin-top: 0px;
    width: 100%;
  }
  .level .concept-pic {
    width: 80%;
    top: 0px;
    margin: auto;
  }
  .level .concept-line {
    height: 6px;
  }
  .level .title-big {
    display: none;
  }

  .level a:nth-child(odd) .concept-text {
    margin: 30px auto 0;
  }

  .level a:nth-child(even) .view:before {
    content: "";
    display: inline-block;
    background-color: #bdbdbd;
    padding-left: 100px;
    padding-top: 1px;
    margin-right: 20px;
    position: relative;
    top: -10px;
    -moz-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
    -o-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
    -webkit-transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
    transition: all 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
  }
  .level a:nth-child(even) .view:after {
    display: none;
  }
  .level a:nth-child(even) .concept-text {
    float: unset;
    text-align: unset;
    margin: 30px auto 0;
  }

  .level a:hover .view:nth-child(even):before {
    padding-left: 150px;
  }
}
@media screen and (max-width: 640px) {
  .level .concept-pic {
    width: 90%;
  }
  .level .concept-text {
    box-shadow: 0 0 0 transparent;
  }
  .level a:hover .concept-text {
    box-shadow: 0 0 0 transparent;
  }

  .top-title {
    left: 10%;
  }
}
@media screen and (max-width: 460px) {
  .level .concept-pic {
    width: 100%;
  }
  .level .concept-text {
    border: 0px;
    margin: 0;
  }
  .level .concept-line {
    height: 2px;
    background: #666;
    width: 250px;
  }
  .level a:hover .concept-text {
    border: 0px solid #000;
  }

  .level a:nth-child(odd) .concept-text {
    margin: 0;
  }
  .level a:nth-child(odd) .concept-line {
    right: 10px;
  }
  .level a:nth-child(odd) .view:before {
    padding-left: 50px;
  }
  .level a:nth-child(odd):hover .concept-line {
    right: 10px;
  }

  .level a:nth-child(even) .concept-text {
    margin: 0;
  }
  .level a:nth-child(even) .concept-line {
    right: 10px;
    left: unset;
  }
  .level a:nth-child(even) .view:before {
    padding-left: 50px;
  }
}
@media screen and (max-height: 650px) {
  .bg {
    height: calc(100vh - 50px);
  }

  .scrolldown {
    bottom: 150px;
  }
}