.grid-wrapper { display: grid; grid-template-rows: 4em 4em 4em 4em 4em 4em 4em; grid-template-columns: 14.3% 14.3% 14.3% 14.3% 14.3% 14.3% 14.3%; width: 70%; border: 1px solid black; } .grid-wrapper .grid-item { border: 2px solid black; } …

#Q98408 { border-collapse: collapse; empty-cells: show; } #Q98408 tr { height: 4em; } #Q98408 td { width: 4em; border: 2px solid black; } HTMLとCSSは、こんな感じ。