diff --git a/colors/onedark.vim b/colors/onedark.vim
index 6dfa2ff..ce0f756 100644
--- a/colors/onedark.vim
+++ b/colors/onedark.vim
@@ -75,7 +75,7 @@ function! s:h(group, style, ...)
     let s:highlight = s:group_colors[a:group]
     for style_type in ["fg", "bg", "sp"]
       if (has_key(a:style, style_type))
-        let l:default_style = (has_key(s:highlight, style_type) ? s:highlight[style_type] : { "cterm16": "NONE", "cterm": "NONE", "gui": "NONE" })
+        let l:default_style = (has_key(s:highlight, style_type) ? copy(s:highlight[style_type]) : { "cterm16": "NONE", "cterm": "NONE", "gui": "NONE" })
         let s:highlight[style_type] = extend(l:default_style, a:style[style_type])
       endif
     endfor