//** Grid Settings **//

//**
  Your basic units for the grid
!grid_unit ||= "em"
!total_cols ||= 16
!col_width ||= 4
!gutter_width ||= 1
!side_gutter_width ||= !gutter_width
!container_width = container(!total_cols, !col_width, !gutter_width, !side_gutter_width)


//** 
  set on the outer grid containing element.
=container(!align = "left")
  //  clear all floated columns
  +clearfix
  //  align the text back to the left (override for other alignments)
  :text-align= !align
  //  use auto horizontal margins to center your page in the body
  :margin
    :left auto
    :right auto
  //  set the page width based on column settings
  :width= !container_width + !grid_unit
  //  never exceed 100% of the browser window (no side-scrolling)
  :max-width 100%


//** 
  set on any column element, even nested ones.
  the first agument [required] is the number of columns to span
  the second argument is the context (columns spanned by parent)
  this is required in any nested context
  by default a grid-col is floated left with a right gutter
  override that with +float("right"), +first or +last
=columns(!n, !context = false)
  //  the width of the column is set as a percentage of the context
  :width= columns(!n, !context) + "%"
  //  the column is floated left
  +float("left")
  //  the right gutter is added as a percentage of the context
  :margin-right= gutter(!context) + "%"

//** 
  set on any column to add empty colums before or after
=prefix(!n, !context = false)
  :padding-left= columns(!n, !context) + gutter(!context) + "%"

=suffix(!n, !context = false)
  :padding-right= columns(!n, !context) + gutter(!context) + "%"

//**  
  set on the first element of a row to take side-gutters into account
  - must override `!nested` for nested columns
=alpha(!nested = false)
  @if !nested
    :margin-left 0
  @else
    :margin-left= side_gutter() + "%"

//**  
  set on the last element of a row to take side-gutters into account
  - must override `!nested` for nested columns
=omega(!n = false)
  @if !n    
    :margin-right= 0
  @else
    :margin-right= side_gutter() + "%"

//**  
  use to override +omega in ie.sass for IE6-7 to handle sub-pixel rounding issues
  - must override `!nested` for nested columns
  - must override `!right` for right-floated omega elements
=ie-omega(!nested = false, !right = false)
  @if !right
    @if !nested    
      :margin-right 0
    @else
      :margin-right= side_gutter() + "%"
    :margin-left -1%
  @else
    @if !nested    
      :margin-right= -1%
    @else
      :margin-right= side_gutter() - 1 + "%"


//**
  set on an element that will span it's entire context
=full(!n = false)
  +alpha(!n)
  +omega(!n)

//**
  set as shortcut for prefix and suffix
=pad(!p = 0, !s = 0, !c = false)
  @if !p != 0
    +prefix(!p,!c)
  @if !s != 0
    +suffix(!s,!c)