Stylelint support (#1025)

.github/workflows/tests.yml

@@ -33,6 +33,7 @@ jobs:
       - run: npm install
       - run: npm run build
       - run: npm run lint
+      - run: npm run stylelint
       - run: npm run test-unit
       - name: "Clean tree"
         run: "npm run test-clean-tree"

.stylelintrc.json

@@ -0,0 +1,40 @@
+{
+    "extends": ["stylelint-config-standard"],
+    "plugins": ["stylelint-csstree-validator"],
+    "ignoreFiles": ["build/**/*.css", "Sources/**/*.css", "docs/**/*.css"],
+    "rules": {
+        "csstree/validator": {
+            "ignoreProperties": ["text-wrap"]
+        },
+        "alpha-value-notation": null,
+        "at-rule-empty-line-before": null,
+        "color-function-notation": null,
+        "color-hex-length": null,
+        "comment-empty-line-before": null,
+        "custom-property-empty-line-before": null,
+        "custom-property-pattern": null,
+        "declaration-block-no-redundant-longhand-properties": null,
+        "declaration-empty-line-before": null,
+        "function-url-quotes": null,
+        "length-zero-no-unit": null,
+        "media-feature-range-notation": null,
+        "no-descending-specificity": null,
+        "property-no-vendor-prefix": null,
+        "rule-empty-line-before": null,
+        "selector-attribute-quotes": null,
+        "selector-class-pattern": null,
+        "selector-pseudo-element-colon-notation": null,
+        "shorthand-property-no-redundant-values": null,
+        "no-duplicate-selectors": null,
+        "comment-whitespace-inside": null,
+        "declaration-block-no-duplicate-properties": null,
+        "value-keyword-case": null,
+        "keyframes-name-pattern": null,
+        "block-no-empty": null,
+        "selector-id-pattern": null,
+        "declaration-block-no-shorthand-property-overrides": null,
+        "font-family-no-missing-generic-family-keyword": null,
+        "font-family-name-quotes": null,
+        "value-no-vendor-prefix": null
+    }
+}