z-index problem only inside the editor

hi
i am adding a style variation to the group block. and it should have a nice box shadow that uses the before and after pseudo elements with a z-index.
all is working great on the front side but the z-index dowsn’t work inside the editor:

this is my css code:

.editor-styles-wrapper
  .wp-block-group.is-style-gutrs-box-shadow-raise-two-sides,
.wp-block-group.is-style-gutrs-box-shadow-raise-two-sides {
  position: relative;

  &:before,
  &:after {
    z-index: -1;
    position: absolute;
    content: "";
    bottom: 15px;
    left: 10px;
    width: 50%;
    top: 80%;
    max-width: 300px;
    background: #777;
    box-shadow: 0 15px 10px #777;
    transform: rotate(-3deg);
  }

  &:after {
    transform: rotate(3deg);
    right: 10px;
    left: auto;
  }
}

i am not sue how to upload the screenshots here but it works great on the front side and not in the editor

any idea?