Lint scss files, Add Github actions for frontend

.github/workflows/frontend.yaml

@@ -0,0 +1,37 @@
+name: Frontend
+
+on:
+    push:
+        branches:
+            - 3.x
+            - master
+        paths:
+            - assets/**
+            - package.json
+            - yarn.lock
+    pull_request:
+        paths:
+            - assets/**
+            - package.json
+            - yarn.lock
+
+jobs:
+    webpack-encore:
+        name: Webpack Encore
+
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
+            - name: Install Node 14
+              uses: actions/setup-node@v2
+              with:
+                  node-version: 14
+
+            - name: Install NPM dependencies
+              uses: bahmutov/npm-install@v1
+
+            - name: Run Webpack Encore
+              run: yarn encore production

.stylelintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": "stylelint-config-standard"
+}

assets/scss/flashmessage.scss

@@ -1,28 +1,28 @@
 .read-more-state {
-    display: none;
+  display: none;
 }
 
 .read-more-target {
-    opacity: 0;
-    display: none;
-    max-height: 0;
-    font-size: 0;
-    transition: .40s ease;
+  opacity: 0;
+  display: none;
+  max-height: 0;
+  font-size: 0;
+  transition: 0.4s ease;
 }
 
 .read-more-state:checked ~ .read-more-wrap .read-more-target {
-    opacity: 1;
-    display: block;
-    font-size: inherit;
-    max-height: 999em;
+  opacity: 1;
+  display: block;
+  font-size: inherit;
+  max-height: 999em;
 }
 
 .read-more-trigger {
-    cursor: pointer;
-    margin: auto;
+  cursor: pointer;
+  margin: auto;
 }
 
 .alert .read-more-trigger {
-    position: relative;
-    left: calc(50% - 1rem);
-}
+  position: relative;
+  left: calc(50% - 1rem);
+}