a[data-tooltip]:link, a[data-tooltip]:visited { position: relative; text-decoration: none; border-bottom: solid 1px; } a[data-tooltip]:before { content: ""; position: absolute; border-top: 1em solid #0090ff; border-left: 1.5em solid transparent; border-right: 1.5em solid transparent; display: none; top: -1em; } a[data-tooltip]:after { content: attr(data-tooltip); position: absolute; color: white; top: -2.5em; left: -1em; background: #0090ff; padding: .25em .75em; border-radius: .5em; white-space: nowrap; display: none; } a[data-tooltip]:hover:before, a[data-tooltip]:hover:after { display: inline; } Code language: CSS (css)