load glassy module only when transparency is enabled

lua/base46/init.lua

@@ -57,7 +57,6 @@ M.turn_str_to_color = function(tb_in)
 end
 
 M.extend_default_hl = function(highlights)
-  local glassy = require "base46.glassy"
   local polish_hl = M.get_theme_tb "polish_hl"
 
   -- polish themes
@@ -71,6 +70,8 @@ M.extend_default_hl = function(highlights)
 
   -- transparency
   if vim.g.transparency then
+    local glassy = require "base46.glassy"
+
     for key, value in pairs(glassy) do
       if highlights[key] then
         highlights[key] = M.merge_tb(highlights[key], value)