This method of underlining works in all browsers I have tested (Windows). It works with long paragraph lengths as well as short. The lines image has lines that are 24 pixels apart. But, because the style is set so that the height uses ems, the image, and therefore the lines, stretch whenever users change the browser's font size settings. (Right click to download the lines image). In all browsers except Internet Explorer, increasing and decreasing text size seems to be done accurately and consistently. Internet Explorer uses proportions I haven't been able to figure out and something is usually "off". The line-height in this example is set to 2em, so the height has to be adjusted accordingly, ie 24 lines x 2 = 48em. As a general rule, the longer the paragraph, the larger the line-height that is needed to accommodate Internet Explorer. Depending on the length of your paragraph, you should try different line-heights and also adjust heights. Strangely, an odd height, such as 36.1em, sometimes works best for IE.