a name="flags" content="ahem" />
        <meta name="assert" content="The 'line-height' property sets a minimum number value." />
        <style type="text/css">* { margin: 0; padding: 0 }
            div
            {
                font: 20px/1 Ahem;
                position: relative;
                width: 1em;
            }
            #div2, #div3
            {
                background: black;
            }
            #div2
            {
                line-height: 0;
            