Sass preprocessor and some style fiexes

package.json

@@ -4,7 +4,7 @@
   "description": "Unreal Engine's Blueprint visualisation library",
   "main": "ueblueprint.js",
   "scripts": {
-    "build": "rollup --config"
+    "build": "rollup --config && sass scss:css --style=compressed"
   },
   "repository": {
     "type": "git",
@@ -27,9 +27,10 @@
     "rollup": "^2.58.0",
     "rollup-plugin-minify-html-template-literals": "^1.2.0",
     "rollup-plugin-terser": "^7.0.2",
+    "sass": "^1.45.1",
     "terser": "^5.9.0"
   },
   "dependencies": {
     "parsimmon": "^1.18.0"
   }
-}
+}