Enable CSS linting (#58)

* Enable CSS linting

* Back out linting of JointJS CSS

* Restore lib CSS

* Revert changes to lib CSS

* Add config

Author: willeastcott

.github/workflows/ci.yml

@@ -36,3 +36,18 @@ jobs:
       run: npm ci
     - name: Run ESLint
       run: npm run lint
+
+  lint-styles:
+    name: Lint Styles
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v2
+    - name: Setup Node.js 16.x
+      uses: actions/setup-node@v2.1.4
+      with:
+        node-version: 16.x
+    - name: Install dependencies
+      run: npm ci
+    - name: Run Stylelint
+      run: npm run lint:styles

.stylelintrc.json

@@ -0,0 +1,19 @@
+{
+    "extends": "stylelint-config-standard-scss",
+    "rules": {
+        "indentation": 4,
+        "font-family-no-missing-generic-family-keyword": [
+            true,
+            {
+                "ignoreFontFamilies": [
+                    "pc-icon"
+                ]
+            }
+        ],
+        "no-descending-specificity": null,
+        "no-duplicate-selectors": null,
+        "scss/no-global-function-names": null,
+        "scss/at-extend-no-missing-placeholder": null,
+        "string-quotes": "single"
+    }
+}