Use custom env for base directory

Enabling override ability needed for GitHub Pages

.github/workflows/deploy.yml

@@ -25,6 +25,8 @@ jobs:
             - run: npm ci
             - name: Build
               run: npm run docs:build
+              env:
+                VITE_BUILD: ${{ env.VITE_BUILD }}
             - uses: actions/configure-pages@v2
             - uses: actions/upload-pages-artifact@v1
               with:

src/.vitepress/config.ts

@@ -1,7 +1,11 @@
-import { defineConfig } from "vitepress";
+import { defineConfig, loadEnv } from "vitepress";
 
 // https://vitepress.dev/reference/site-config
-export default defineConfig({
+export default ({ mode }) => {
+	// Load app-level env vars to node-level env vars.
+	process.env = { ...process.env, ...loadEnv(mode, process.cwd()) };
+
+	return defineConfig({
 		lang: "en-US",
 		title: "Tachiyomi",
 		description: "Free and open source manga reader for Android",
@@ -9,6 +13,9 @@ export default defineConfig({
 		lastUpdated: true,
 		cleanUrls: true,
 
+		// Base directory, enabling override ability needed for GitHub Pages
+		base: process.env.VITE_BASE || "/",
+
 		head: [["meta", { name: "theme-color", content: "#4A74EA" }]],
 
 		themeConfig: {
@@ -35,6 +42,7 @@ export default defineConfig({
 			socialLinks: [{ icon: "github", link: "https://github.com/vuejs/vitepress" }],
 		},
 	});
+};
 
 function nav() {
 	return [