diff --git a/autoload/goyo.vim b/autoload/goyo.vim
index e66c5c1..c8f32c3 100644
--- a/autoload/goyo.vim
+++ b/autoload/goyo.vim
@@ -33,7 +33,7 @@ function! s:get_color(group, attr)
 endfunction
 
 function! s:set_color(group, attr, color)
-  let gui = has('gui_running')
+  let gui = a:color =~ '^#'
   execute printf("hi %s %s%s=%s", a:group, gui ? 'gui' : 'cterm', a:attr, a:color)
 endfunction