schlechtenburg/packages/core/lib/components/BlockPlaceholder.scss

.sb-block-placeholder {
  width: 100%;
  position: relative;
  overflow: visible;

  &__add {
    background-color: var(--grey-1);
    width: 100%;
  }

  .sb-block-picker {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100%;
    width: 100%;
  }
}