Add embedded gists & JSON gist data/metadata (#179)

postcss.config.js

@@ -1,7 +1,10 @@
 module.exports = {
   plugins: {
+    'postcss-import': {},
+    'tailwindcss/nesting': {},
     tailwindcss: {},
     autoprefixer: {},
+    'postcss-selector-namespace': {namespace() {return (process.env.EMBED) ? '.opengist-embed' : '';}},
     cssnano: {},
   },
 }