html,
body {
  padding: 0;
  margin: 0;
  overflow-x: hidden;
}
@keyframes circle {
  0% {
    opacity: 0.6;
    width: 100%;
    height: 100%;
  }
  25% {
    opacity: 0.4;
    width: 115%;
    height: 115%;
  }
  50% {
    opacity: 0.2;
    width: 130%;
    height: 130%;
  }
  75% {
    opacity: 0.1;
    width: 145%;
    height: 145%;
  }
  100% {
    opacity: 0;
    width: 160%;
    height: 160%;
  }
}
.pages_index img {
  display: block;
}
.pages_index a {
  text-decoration: none;
}
.pages_index ul,
.pages_index li {
  list-style: none;
}
.pages_index .w {
  max-width: 1440px;
  margin: 0 auto;
  margin-top: -138px;
  position: relative;
  z-index: 2;
}
.pages_index .w2 {
  max-width: 1024px;
  margin: 0 auto;
}
.pages_index .banner {
  position: relative;
}
.pages_index .banner .codechina {
  position: absolute;
  width: 8.2%;
  height: 4.2%;
  top: 2.8%;
  left: 11.6%;
}
.pages_index .banner .help {
  position: absolute;
  width: 10%;
  height: 4.2%;
  top: 2.8%;
  left: 23%;
}
.pages_index .title {
  padding: 0 270px;
  box-sizing: border-box;
  background: url(../img/title_l.png) left no-repeat, url(../img/title_r.png) right no-repeat;
  width: max-content;
  margin: 80px auto;
  font-size: 40px;
  font-weight: 500;
  margin-top: 120px;
}
.pages_index p {
  font-size: 25px;
  color: #172853;
  text-align: center;
  margin-bottom: 60px;
}
.pages_index .tab {
  border: 2px solid #4e5595;
  border-radius: 8px;
  width: 650px;
  height: 64px;
  margin: 0 auto;
  line-height: 64px;
  display: flex;
  justify-content: space-between;
}
.pages_index .tab .item {
  color: #172853;
  font-size: 25px;
  width: 50%;
  text-align: center;
  height: 100%;
  cursor: pointer;
}
.pages_index .tab .item.active {
  background: #4e5595;
  color: #fff;
}
.pages_index h3 {
  text-align: center;
  font-size: 30px;
  color: #172853;
  margin: 100px 0;
}
.pages_index .project_list {
  display: flex;
  justify-content: space-between;
}
.pages_index .project_list .item {
  display: flex;
}
.pages_index .project_list .item img {
  width: 200px;
  height: 272px;
  border-radius: 8px;
}
.pages_index .project_list .item ul {
  flex: 1;
  padding: 0 32px;
  margin: 0;
}
.pages_index .project_list .item ul li {
  font-size: 25px;
}
.pages_index .project_list .item ul li + li {
  margin-top: 33px;
}
.pages_index .project_list .item ul .bookname {
  font-size: 30px;
  font-weight: 500;
  color: #172853;
}
.pages_index .project_list .item ul a,
.pages_index .project_list .item ul span {
  margin-left: 24px;
}
.pages_index .project_list .item ul a {
  color: #409eff;
  text-decoration: underline;
}
.pages_index .project_list .item ul .desc {
  font-size: 16px;
  color: #4c4c4c;
  padding: 18px 22px;
  background: rgba(251, 239, 216, 0.5);
  border-radius: 8px;
}
.pages_index .steps {
  margin-top: 100px;
}
.pages_index .steps .step_item {
  border-left: 3px solid #4e5595;
  position: relative;
  padding-left: 70px;
  color: #172853;
  padding-bottom: 100px;
}
.pages_index .steps .step_item.hidden {
  display: none;
}
.pages_index .steps .step_item:last-child {
  border: none;
}
.pages_index .steps .step_item::before,
.pages_index .steps .step_item::after {
  display: block;
  content: "";
  height: 1px;
}
.pages_index .steps .step_item img {
  border: 2px solid #409eff;
  border-radius: 8px;
  margin-top: 50px;
}
.pages_index .steps .step_item .index {
  position: absolute;
  width: 64px;
  height: 64px;
  line-height: 64px;
  text-align: center;
  font-size: 30px;
  color: #fff;
  top: 0px;
  left: -32px;
  background: #4e5595;
  border-radius: 50%;
}
.pages_index .steps .step_item h4 {
  font-size: 25px;
  margin: 14px 0;
}
.pages_index .steps .step_item p {
  font-size: 20px;
  text-align: left;
  margin: 40px 0;
}
.pages_index .steps .step_item code {
  display: block;
  color: #fff;
  background: #3d3d3d;
  font-size: 20px;
  position: relative;
  border-radius: 8px;
  border: 1px solid #3d3d3d;
  overflow: hidden;
  padding: 48px 20px 20px;
  line-height: 36px;
}
.pages_index .steps .step_item code::before {
  position: absolute;
  content: "";
  width: 100%;
  height: 28px;
  background: #c4c4c4;
  top: 0;
  left: 0;
}
.pages_index .visit {
  width: 156px;
  margin: 30px auto;
  position: relative;
}
.pages_index .visit img {
  width: 156px;
  height: 156px;
  border-radius: 50%;
  cursor: pointer;
  position: relative;
  z-index: 9;
}
.pages_index .visit .circle {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  border: 5px solid #4e5595;
  box-sizing: border-box;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  -o-transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  -moz-transform: translate(-50%, -50%);
  -webkit-transform: translate(-50%, -50%);
  animation: circle 4s linear infinite;
}
.pages_index .visit .circle.circle2 {
  animation-delay: 1.3s;
}
.pages_index .visit .circle.circle3 {
  animation-delay: 2.5s;
}
.pages_index .buttons {
  display: flex;
  justify-content: space-between;
  margin: 100px auto 200px;
}
.pages_index .buttons .btn {
  width: 288px;
  height: 64px;
  line-height: 64px;
  text-align: center;
  font-size: 25px;
  color: #172853;
  border: 2px solid #4e5595;
  border-radius: 8px;
  display: block;
  box-sizing: border-box;
  cursor: pointer;
  font-weight: 500;
}
.pages_index .buttons .btn.active {
  border: none;
  background: linear-gradient(90deg, #78568c 0%, #4e5595 100%);
  color: #fff;
}
.pages_index .footer {
  width: 100%;
  text-align: center;
  color: #fff;
  font-size: 20px;
  height: 102px;
  line-height: 102px;
  background: #4e5595;
}