.block-editor-block-list__layout .wp-block, 
.block-editor-block-list__layout [class^='wp-block'] {

  margin-left: auto;
  margin-right: auto;
  margin-top: 1.5rem;
  margin-bottom: 1.5rem;
  max-width: 1280px;
  padding: 0px;
  width:auto;
  
}