sub get_random_color {
    my %color = (
        red  => f00, yellow  => ff0, green => 0f0, cyan  => 0ff,
        blue => 00f, magenta => f0f, white => fff, black => 000
    );
    my $choice = (keys %color)[rand keys %color];
    return '<span class="mut" style="color:' . $color{$choice} . ';">' . $choice . '</span>';
}