<!DOCTYPE HTML> <style> body { width: 450px } body, select { font-size: 12px } </style> <!-- In a 450px container, the minimum font size at 15em per line is 30px. This means we map 0px-45px into 30px-45px, so 12px gets mapped to 34px. --> <select> <optgroup label="Counties"> <option>Arlington <option>Fairfax <option>Loudon <option>Prince William <optgroup label="Cities"> <option>Alexandria <option>Falls Church <option>Manassas <option>Manassas Park </select>