PolinaD

position:relative;
    &:before,
    &:after{
      content:'';
      position: absolute;
      background:inherit;
      display: block;
      top:0;
      bottom: 0;
      width: 100%;
    }
    &:before{
      right: 100%;
    }
    &:after{
      left: 100%;
    }