Restore initial styles in AtomEnvironment::reset

src/atom-environment.coffee

@@ -156,6 +156,7 @@ class AtomEnvironment extends Model
       packageManager: @packages, configDirPath, resourcePath, safeMode, @config,
       styleManager: @styles, notificationManager: @notifications, viewRegistry: @views
     })
+    @initialStyleElements = @styles.getSnapshot()
 
     MenuManager = require './menu-manager'
     @menu = new MenuManager({resourcePath, keymapManager: @keymaps, packageManager: @packages})
@@ -242,6 +243,8 @@ class AtomEnvironment extends Model
     @commands.clear()
     registerDefaultCommands(this)
 
+    @styles.restoreSnapshot(@initialStyleElements)
+
   ###
   Section: Event Subscription
   ###