rollback css-loader version to 3.6.0

webpack-contrib/css-loader#1134

Author: tarnishablec

.gitignore

@@ -6,6 +6,7 @@ coverage
 
 lerna-debug.log
 yarn-error.log
+debug.log
 
 .travis.yml
 

package.json

@@ -54,7 +54,7 @@
     "copy-webpack-plugin": "^6.0.3",
     "coveralls": "^3.1.0",
     "cross-env": "^7.0.2",
-    "css-loader": "^4.0.0",
+    "css-loader": "3.6.0",
     "electron": "^9.1.1",
     "eslint": "^7.5.0",
     "execa": "^4.0.3",

packages/doc/debug.log

@@ -99,6 +99,7 @@ play-ground {
   width: 100%;
   top: var(--header-height);
   z-index: 1;
+  background: rgba(100, 100, 100, 0.6);
   transform: translateY(-100%);
   transition: transform 0.2s ease-in-out;