Add stylelint to run linter for docsify style

.circleci/config.yml

@@ -22,7 +22,13 @@ references:
           name: Prettier formatting
           command: yarn format:check
 
-      - run: yarn lint:all
+      - run:
+          name: ESLint
+          command: yarn lint:js
+
+      - run:
+          name: stylelint
+          command: yarn lint:css
 
       - run:
           name: Jest

.stylelintrc.yml

@@ -0,0 +1,17 @@
+extends:
+  - stylelint-config-standard
+  - stylelint-config-prettier
+
+ignoreFiles:
+  - coverage/**/*
+  - docs/style/**/*
+  - jsdoc/**/*
+
+plugins:
+  - stylelint-scss
+
+rules:
+  at-rule-no-unknown:
+    - null
+  scss/at-rule-no-unknown:
+    - true

package.json

@@ -45,10 +45,10 @@
     "format": "prettier \"**/*.{css,js,json,md,scss,ts,yaml,yml}\"",
     "format:check": "yarn --silent --mutex file run format -l",
     "jsdoc": "rimraf jsdoc && jsdoc src -c .jsdoc.json",
-    "lint": "eslint",
-    "lint:all": "eslint .",
-    "prepack": "npm-run-all --npm-path yarn --parallel format:check lint:all test:coverage --sequential build",
-    "preversion": "npm-run-all --npm-path yarn --parallel format:check lint:all test:coverage",
+    "lint:js": "eslint .",
+    "lint:css": "stylelint \"./**/*.{css,scss}\"",
+    "prepack": "npm-run-all --npm-path yarn --parallel format:check lint:* test:coverage --sequential build",
+    "preversion": "npm-run-all --npm-path yarn --parallel format:check lint:* test:coverage",
     "test": "jest",
     "test:coverage": "jest --coverage",
     "version": "node version.js && git add -A CHANGELOG.md",
@@ -82,7 +82,11 @@
     "nodemon": "^1.18.6",
     "npm-run-all": "^4.1.3",
     "prettier": "^1.14.3",
-    "rimraf": "^2.6.2"
+    "rimraf": "^2.6.2",
+    "stylelint": "^9.8.0",
+    "stylelint-config-prettier": "^4.0.0",
+    "stylelint-config-standard": "^18.2.0",
+    "stylelint-scss": "^3.4.0"
   },
   "dependencies": {
     "js-yaml": "^3.12.0",