diff --git a/README.md b/README.md
index fc21bb7..c1b3ab6 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ Lean & mean statusline for vim that's light as air.
 
 # Features
 
-*  tiny core (under 200 lines), written with extensibility in mind ([open/closed principle][8]).
+*  tiny core written with extensibility in mind ([open/closed principle][8]).
 *  integrates with a variety of plugins, including: [vim-bufferline][6], [fugitive][4], [unite][9], [ctrlp][10], [minibufexpl][15], [gundo][16], [undotree][17], [nerdtree][18], [tagbar][19], [syntastic][5] and [lawrencium][21].
 *  looks good with regular fonts and provides configuration points so you can use unicode or powerline symbols.
 *  optimized for speed; it loads in under a millisecond.
diff --git a/autoload/airline.vim b/autoload/airline.vim
index fb82d11..013a446 100644
--- a/autoload/airline.vim
+++ b/autoload/airline.vim
@@ -4,10 +4,6 @@
 let s:sections = ['a','b','c','gutter','x','y','z','warning']
 let s:highlighter = airline#highlighter#new()
 
-function! airline#get_highlighter()
-  return s:highlighter
-endfunction
-
 function! airline#reload_highlight()
   call s:highlighter.highlight(['inactive'])
   call s:highlighter.highlight(['normal'])
@@ -23,7 +19,6 @@ function! airline#load_theme(name)
   call airline#check_mode()
 endfunction
 
-
 function! s:get_section(winnr, key, ...)
   let text = airline#util#getwinvar(a:winnr, 'airline_section_'.a:key, g:airline_section_{a:key})
   let [prefix, suffix] = [get(a:000, 0, '%( '), get(a:000, 1, ' %)')]
diff --git a/autoload/airline/builder.vim b/autoload/airline/builder.vim
index db590d8..1332b04 100644
--- a/autoload/airline/builder.vim
+++ b/autoload/airline/builder.vim
@@ -27,7 +27,6 @@ function! airline#builder#new(active, highlighter)
     let line = '%{airline#check_mode()}'
     let side = 0
     let prev_group = ''
-    let separator_groups = []
     for section in self._sections
       if section[0] == '|'
         let side = 1
@@ -41,13 +40,10 @@ function! airline#builder#new(active, highlighter)
       endif
 
       if prev_group != ''
-        let sep = side == 0
-              \ ? [self._group(section[0]), self._group(prev_group)]
-              \ : [self._group(prev_group), self._group(section[0])]
-        call add(separator_groups, sep)
+        call self._highlighter.add_separator(self._group(prev_group), self._group(section[0]))
         let line .= side == 0
-              \ ? '%#'.self._group(section[0].'_to_'.prev_group).'#'
-              \ : '%#'.self._group(prev_group.'_to_'.section[0]).'#'
+              \ ? '%#'.self._group(section[0]).'_to_'.self._group(prev_group).'#'
+              \ : '%#'.self._group(prev_group).'_to_'.self._group(section[0]).'#'
         let line .= side == 0
               \ ? self._active ? g:airline_left_sep : g:airline_left_alt_sep
               \ : self._active ? g:airline_right_sep : g:airline_right_alt_sep
@@ -59,7 +55,6 @@ function! airline#builder#new(active, highlighter)
 
     return {
           \ 'statusline': line,
-          \ 'separator_groups': separator_groups,
           \ }
   endfunction
 
diff --git a/autoload/airline/highlighter.vim b/autoload/airline/highlighter.vim
index 284ab51..016192e 100644
--- a/autoload/airline/highlighter.vim
+++ b/autoload/airline/highlighter.vim
@@ -10,13 +10,13 @@ function! airline#highlighter#exec(group, colors)
   endif
   exec printf('hi %s %s %s %s %s %s %s %s',
         \ a:group,
-        \ colors[0] != '' ? 'guifg='.colors[0] : '',
-        \ colors[1] != '' ? 'guibg='.colors[1] : '',
-        \ colors[2] != '' ? 'ctermfg='.colors[2] : '',
-        \ colors[3] != '' ? 'ctermbg='.colors[3] : '',
-        \ len(colors) > 4 && colors[4] != '' ? 'gui='.colors[4] : '',
-        \ len(colors) > 4 && colors[4] != '' ? 'cterm='.colors[4] : '',
-        \ len(colors) > 4 && colors[4] != '' ? 'term='.colors[4] : '')
+        \ get(colors, 0, '') != '' ? 'guifg='.colors[0] : '',
+        \ get(colors, 1, '') != '' ? 'guibg='.colors[1] : '',
+        \ get(colors, 2, '') != '' ? 'ctermfg='.colors[2] : '',
+        \ get(colors, 3, '') != '' ? 'ctermbg='.colors[3] : '',
+        \ get(colors, 4, '') != '' ? 'gui='.colors[4] : '',
+        \ get(colors, 4, '') != '' ? 'cterm='.colors[4] : '',
+        \ get(colors, 4, '') != '' ? 'term='.colors[4] : '')
 endfunction
 
 function! airline#highlighter#exec_separator(from, to)
@@ -30,9 +30,13 @@ function! airline#highlighter#exec_separator(from, to)
   return group
 endfunction
 
-
 function! airline#highlighter#new()
   let highlighter = {}
+  let highlighter._separators = []
+
+  function! highlighter.add_separator(from, to)
+    call add(self._separators, [a:from, a:to])
+  endfunction
 
   function! highlighter.highlight(modes)
     " draw the base mode, followed by any overrides
@@ -46,7 +50,9 @@ function! airline#highlighter#new()
         endfor
       endif
     endfor
-    for sep in w:airline_current_info.separator_groups
+
+    " synchronize separator colors
+    for sep in self._separators
       call airline#highlighter#exec_separator(sep[0].suffix, sep[1].suffix)
     endfor
   endfunction