.content-main {
  position: relative;
  width: 100%;
  margin: 40px auto;
}
.content-main .content-box {
  height: auto;
  overflow: hidden;
  padding: 20px;
  background: #fff;
  box-shadow: 6px 10px 10px rgba(0, 0, 0, 0.1);
}
.content-main .content-box:before, .content-main .content-box:after {
  content: "";
  height: 2px;
  position: absolute;
  left: 0;
  right: 0;
  -webkit-clip-path: polygon(0% 0%, 5% 100%, 10% 0%, 15% 100%, 20% 0%, 25% 100%, 30% 0%, 35% 100%, 40% 0%, 45% 100%, 50% 0%, 55% 100%, 60% 0%, 65% 100%, 70% 0%, 75% 100%, 80% 0%, 85% 100%, 90% 0%, 95% 100%, 100% 0%);
}
.content-main .content-box:before {
  background-color: #eee;
  top: 0;
}
.content-main .content-box:after {
  background-color: #fff;
  bottom: -2px;
}