③【ツール】診断スタイルシート

div:empty, span:empty,

li:empty, p:empty,

td:empty, th:empty {padding: 0.5em; background: yellow;}

*[style], font, center {outline: 5px solid red;}

*[class=""], *[id=""] {outline: 5px dotted red;}

img[alt=""] {border: 3px dotted red;}

img:not([alt]) {border: 5px solid red;}

img[title=""] {outline: 3px dotted fuchsia;}

img:not([title]) {outline: 5px solid fuchsia;}

table:not([summary]) {outline: 5px solid red;}

table[summary=""] {outline: 3px dotted red;}

th {border: 2px solid red;}

th[scope="col"], th[scope="row"] {border: none;}

a[href]:not([title]) {border: 5px solid red;}

a[title=""] {outline: 3px dotted red;}

a[href="#"] {background: lime;}

a[href=""] {background: fuchsia;} 

div {outline: 1px dashed red;}