getLeft(args)
    if length(args) == 4
        args[3]
    else if length(args) > 1
        args[1]
    else
        args
getTop(args)
    if length(args) > 1
        args[0]
    else 
        args
getRight(args)
    if length(args) > 1
        args[1]
    else 
        args
getBottom(args)
    if length(args) >= 3
        args[2]
    else if length(args) > 1
        args[0]
    else
        args

clearfix()
    zoom 1
    &:after
        display table
        clear both
        content ''
        height 0

add(main, args...)
    if unit(main) == 'rem' || unit(main) == 'em'
        for arg in args
            main = main + unit(arg / $rem, rem)
    else
        for arg in args
            main = main + unit(arg, px)

    return main

hsv(h-hsv, s-hsv, v-hsv, a = 1)
    if v-hsv == 0
        return hsla(0, 0, 0, a)
    else
        s-hsv = unit(s-hsv, '')
        v-hsv = unit(v-hsv, '')
        l-hsl = (v-hsv / 2) * (2 - (s-hsv / 100))
        if l-hsl == 0 || l-hsl == 100
            s-hsl = l-hsl 
        else 
            s-hsl = (v-hsv * s-hsv) / (l-hsl < 50 ? l-hsl * 2 : 200 - l-hsl * 2)
        return hsla(h-hsv, s-hsl, l-hsl, a)

toHsv(color)
    r = red(color);
    g = green(color);
    b = blue(color);
    return rgbToHsv(r, g, b)

hsvhue(color)
    hsv = toHsv(color);
    return unit(hsv.h, '')

hsvsaturation(color)
    hsv = toHsv(color);
    return unit(hsv.s, '%')

hsvvalue(color)
    hsv = toHsv(color);
    return unit(hsv.v, '%')

rgbToHsv(r, g, b)
    r = (r / 255);
    g = (g / 255);
    b = (b / 255);
    max = max(max(r, g), b);
    min = min(min(r, g), b);
    h = s = v = max;
    d = max - min;
    s = (max == 0) ? 0 : (d / max);
    if max == min
        h = 0;
    else
        if max == r
            h = ((g - b) / d) + (g < b ? 6 : 0);
        else if max == g
            h = ((b - r) / d) + 2;
        else if max == b
            h = ((r - g) / d) + 4;

    h = (h / 6);

    return { h: h * 360, s: s * 100, v: v * 100 }

palette(color, level)
    h = hsvhue(color)
    s = hsvsaturation(color)
    b = hsvvalue(color)

    if s <= 10% 
        deS = 0
    else
        deS = (s - 10%) / 4
    inS = (100% - s) / 4
    deB = (100% - b) / 4
    if b <= 40%
        inB = 0
    else 
        inB = (b - 40%) / 4

    if (level < 0 && level >= -4)
        return hsv(h + level, s + level * deS, b - level * deB)
    else if (level > 0 && level <= 4)
        return hsv(h + level, s + level * inS, b - level * inB)
    else
        return color

requireTheme(name)
    for dir in $theme-dir
        require(name + '.styl', dir)