z-index

position 이 들어가야 z-index가 먹는다.

https://aboooks.tistory.com/83

 .textBox {
      position: relative;
      .title {
        position: relative;
        z-index: 2;
        @include title-font-pc;
      }
      .text {
        position: relative;
        z-index: 2;
        @include text-font-pc;
        word-break: keep-all;
        margin-top: REM(16);
      }
    }

    .textBox:after {
      z-index: 1;
      @include deco-icon("/kci/graph.png", 238px, 218px);
      position: absolute;
      top: 0;
      right: 0;
    }