site: fix site on mobile (#597)

Signed-off-by: Bobby DeSimone <bobbydesimone@gmail.com>

docs/.vuepress/theme/index.js

@@ -1,52 +1,3 @@
-const path = require("path");
-
-// Theme API.
-module.exports = (options, ctx) => ({
-  alias() {
-    const { themeConfig, siteConfig } = ctx;
-    // resolve algolia
-    const isAlgoliaSearch =
-      themeConfig.algolia ||
-      Object.keys((siteConfig.locales && themeConfig.locales) || {}).some(
-        base => themeConfig.locales[base].algolia
-      );
-    return {
-      "@AlgoliaSearchBox": isAlgoliaSearch
-        ? path.resolve(__dirname, "components/AlgoliaSearchBox.vue")
-        : path.resolve(__dirname, "noopModule.js")
-    };
-  },
-
-  plugins: [
-    ["@vuepress/active-header-links", options.activeHeaderLinks],
-    "@vuepress/search",
-    "@vuepress/plugin-nprogress",
-    [
-      "container",
-      {
-        type: "tip",
-        defaultTitle: {
-          "/zh/": "提示"
-        }
-      }
-    ],
-    [
-      "container",
-      {
-        type: "warning",
-        defaultTitle: {
-          "/zh/": "注意"
-        }
-      }
-    ],
-    [
-      "container",
-      {
-        type: "danger",
-        defaultTitle: {
-          "/zh/": "警告"
-        }
-      }
-    ]
-  ]
-});
+module.exports = {
+  extend: '@vuepress/theme-default'
+}