.stylelintrc

{
   "extends": ["@gitlab/stylelint-config"],
   "ignoreFiles": [
     "app/assets/stylesheets/pages/emojis.scss",
     "app/assets/stylesheets/startup/startup-*.scss",
     "app/assets/stylesheets/lazy_bundles/select2.scss",
     "app/assets/stylesheets/highlight/themes/*.scss",
     "app/assets/stylesheets/lazy_bundles/cropper.css"
   ],
   "plugins":[
      "./scripts/frontend/stylelint/stylelint-duplicate-selectors.js",
      "./scripts/frontend/stylelint/stylelint-utility-classes.js",
   ],
   "rules":{
      "at-rule-disallowed-list": [
         "debug"
      ],
      "at-rule-no-unknown": null,
      "at-rule-no-vendor-prefix": true,
      "block-no-empty": true,
      "block-opening-brace-space-before": "always",
      "color-hex-case": "lower",
      "color-hex-length": "short",
      "color-named": "never",
      "color-no-invalid-hex": true,
      "declaration-bang-space-after": "never",
      "declaration-bang-space-before": "always",
      "declaration-block-semicolon-newline-after": "always",
      "declaration-block-semicolon-space-before": "never",
      "declaration-block-single-line-max-declarations": 1,
      "declaration-block-trailing-semicolon": "always",
      "declaration-colon-space-after": "always-single-line",
      "declaration-colon-space-before": "never",
      "declaration-property-value-disallowed-list": {
         "border":[
            "none"
         ],
         "border-top":[
            "none"
         ],
         "border-right":[
            "none"
         ],
         "border-bottom":[
            "none"
         ],
         "border-left":[
            "none"
         ]
      },
      "function-comma-space-after": "always-single-line",
      "function-parentheses-space-inside": "never",
      "function-url-quotes": "always",
      "indentation": 2,
      "length-zero-no-unit": true,
      "max-nesting-depth": [
         6,
         {
            "ignoreAtRules":[
               "each",
               "media",
               "supports",
               "include"
            ],
            "severity":"warning"
         }
      ],
      "media-feature-name-no-vendor-prefix":true,
      "media-feature-parentheses-space-inside":"never",
      "no-missing-end-of-source-newline":true,
      "number-leading-zero":"always",
      "number-no-trailing-zeros":true,
      "property-no-unknown":true,
      "property-no-vendor-prefix": [true, { "ignoreProperties": ["user-select"] }],
      "rule-empty-line-before":[
         "always-multi-line",
         {
            "except":[
               "first-nested"
            ],
            "ignore":[
               "after-comment"
            ]
         }
      ],
      "scss/at-extend-no-missing-placeholder":[true,{ "severity": "warning" }],
      "scss/at-function-pattern":"^[a-z]+([a-z0-9-]+[a-z0-9]+)?$",
      "scss/at-import-no-partial-leading-underscore":true,
      "scss/at-import-partial-extension-blacklist":[
         "scss"
      ],
      "scss/at-mixin-pattern":"^[a-z]+([a-z0-9-]+[a-z0-9]+)?$",
      "scss/at-rule-no-unknown":true,
      "scss/dollar-variable-colon-space-after":"always",
      "scss/dollar-variable-colon-space-before":"never",
      "scss/dollar-variable-pattern":"^[_]?[a-z]+([a-z0-9-]+[a-z0-9]+)?$",
      "scss/percent-placeholder-pattern":"^[a-z]+([a-z0-9-]+[a-z0-9]+)?$",
      "scss/selector-no-redundant-nesting-selector":true,
      "selector-class-pattern":[
         "^[a-z0-9\\-]+$",
         {
            "message":"Selector should be written in lowercase with hyphens (selector-class-pattern)",
            "severity": "warning"
         }
      ],
      "selector-list-comma-newline-after":"always",
      "selector-max-compound-selectors":[6, { "severity": "warning" }],
      "selector-max-id":1,
      "selector-no-vendor-prefix":true,
      "selector-pseudo-element-colon-notation":"double",
      "selector-pseudo-element-no-unknown":true,
      "shorthand-property-no-redundant-values":true,
      "string-quotes":"single",
      "value-no-vendor-prefix": [true, { "ignoreValues": ["sticky"] }],
      "stylelint-gitlab/utility-classes":[true,{ "severity": "warning" }],
      "declaration-block-no-duplicate-properties": [
        true,
        {
          "ignore": ["consecutive-duplicates"]
        }
      ],
      "no-eol-whitespace": true,
   }
}