Merge branch 'master' of https://github.com/vuejs/vuepress

Author: ulivz

packages/docs/docs/guide/basic-config.md

@@ -34,7 +34,7 @@ You can also use YAML (`.vuepress/config.yml`) or TOML (`.vuepress/config.toml`)
 
 A VuePress theme is responsible for all the layout and interactivity details of your site. VuePress ships with a default theme (you are looking at it right now) which is designed for technical documentation. It exposes a number of options that allow you to customize the navbar, sidebar and homepage, etc. For details, check out the [Default Theme Config](../theme/default-theme-config.md) page.
 
-If you wish to develop a custom theme, see [Custom Themes](custom-themes.md).
+If you wish to develop a custom theme, see [Writing a theme](../theme/writing-a-theme.md).
 
 ## App Level Enhancements