Help:Tooltips

Any element on your page which needs to have a tooltip has to be given at least one of the position classes: hint--top, hint--bottom, hint--left, hint--right to position the tooltip, and the tooltip text has to be given using the data-hint attribute on that element. Can be used with other available modifiers in various combinations. Available modifiers: hint--error, hint--info, hint--warning, hint--success, hint--rounded and hint--bounce. Remember space and double dash.

Hello Sir, hover over me.

Result: Hello Sir, hover over me. More examples: top-error, left-info, right-warning, top-success, left-rounded, right-bounce.

But it still can't be used when the tooltip contains superscript.

Thanks to these guys and these guys.