.abso-center {
  left: 0;
  right: 0;
  margin: 0 auto;
}
.abso-center-y {
  left: 0;
  right: 0;
  margin: 0 auto;
  top: 20%;
}

.bg {
  width: 100%;
}
.imgtitle{
  width: 50%;
  position: absolute;
  top: 11%;
}
.imgbox{
  width: 86%;
  display: block;
  position: absolute;
  top: 22%;
}
.imgstart{
  width: 36%;
  display: block;
  position: absolute;
  top: 72%;
}

#draw_container {
  position: absolute;
  top: 25%;
  left: 0;
  right: 0;
  margin: 0 auto;
  width: 76%;
}

#draw_container > ul {
  width: 100%;
  height: 100%;
  overflow: hidden;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  box-sizing: border-box;
}

#draw_container > ul > li {
  position: relative;
  width: 28%;
  margin-bottom: 4%;
  background: #302859;
  border-radius: 15px;
}
#draw_container > ul > li > img {
  width: 100%;
  display: block;
}
#oUl li .mask {
  width: 100%;
  height: 100%;
  position: absolute;
  left: 0;
  top: 0;
  background: url(../img/draw-xz.png) no-repeat;
  background-size: cover;
  display: none;
}
#oUl .active .mask {
  display: block;
}