Move files.

assets/css/main.scss

@@ -8,9 +8,9 @@
 * MIT Licensed
 */
 
-@import "_fonts";
-@import "_module";
-@import "_variables";
+@import "_addon/fonts";
+@import "_addon/module";
+@import "_addon/variables";
 @import "_colors/light-typography";
 @import "_colors/dark-typography";
 

assets/css/post.scss

@@ -7,7 +7,7 @@
   © 2019 Cotes Chung
   MIT License
 */
-@import "_variables";
+@import "_addon/variables";
 
 $prompt-older: "{{ site.data.label.post.button.previous }}";
 $prompt-newer: "{{ site.data.label.post.button.next }}";