fix(docs): update concept-theme-system.md (#602)

Change Currently, there are 2 built-in themes: to Currently, there are 2 built-in themes:
akveo · Aug 6, 2018 · 95fbe74 · 95fbe74
1 parent 7d8beea
commit 95fbe74
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/docs/articles/concept-theme-system.md b/docs/articles/concept-theme-system.md
@@ -91,7 +91,7 @@ Depending on the currently enabled theme and the way `card-bg` inherited in your
 
 ## Built-in themes
 
-Currently, there are 2 built-in themes: 
+Currently, there are 3 built-in themes: 
 - `default` - clean white theme
 - `cosmic` - dark theme
 - `corporate` - firm business theme