#yy_case {
  width: 100%;
  background-color: #f2f2f2;
}
#yy_case .yy_case {
  width: 1200px;
  margin: 0 auto;
  margin-top: -30px;
  padding-top: 84px;
  box-sizing: border-box;
  padding-bottom: 89px;
}
#yy_case .yy_case h3 {
  text-align: center;
  font-size: 48px;
  font-family: Microsoft YaHei;
  font-weight: 400;
  color: #202020;
}
#yy_case .yy_case ul {
  display: flex;
  justify-content: space-around;
  margin-top: 77px;
}