body.wp-admin section{border:1px solid #ccc}body.wp-admin section .container .grid:empty:before{color:red;font-weight:600;content:"This is an empty *block* - add content";padding:2rem 0;display:block}body.wp-admin section .container .grid .col:empty:before{color:red;font-weight:600;content:"This is an empty *column* - add content";padding:2rem 0;display:block}