def estimate_label_width(labels):
    """
    Given a list of labels, estimate the width in pixels
    and return in a format accepted by CSS.
    Necessarily an approximation, since the font is unknown
    and is usually proportionally spaced.
    """
    max_length = max([len(l) for l in labels])
    return "{0}px".format(max(60,int(max_length*7.5)))