text: # selector-pseudo-element-no-unknown
  
  Disallow unknown pseudo-element selectors.
  
  <!-- prettier-ignore -->
  ```css
    a::before {}
  /**  ↑
   * This pseudo-element selector */
  ```
  
  This rule considers pseudo-element selectors defined in the CSS Specifications, up to and including Editor's Drafts, to be known.
  
  This rule ignores vendor-prefixed pseudo-element selectors.
  
  ## Options
  
  ### `true`
  
  The following patterns are considered violations:
  
  <!-- prettier-ignore -->
  ```css
  a::pseudo {}
  ```
  
  <!-- prettier-ignore -->
  ```css
  a::PSEUDO {}
  ```
  
  <!-- prettier-ignore -->
  ```css
  a::element {}
  ```
  
  The following patterns are _not_ considered violations:
  
  <!-- prettier-ignore -->
  ```css
  a:before {}
  ```
  
  <!-- prettier-ignore -->
  ```css
  a::before {}
  ```
  
  <!-- prettier-ignore -->
  ```css
  ::selection {}
  ```
  
  <!-- prettier-ignore -->
  ```css
  input::-moz-placeholder {}
  ```
  
  ## Optional secondary options
  
  ### `ignorePseudoElements: ["/regex/", "string"]`
  
  Given:
  
  ```
  ["/^my-/", "pseudo-element"]
  ```
  
  The following patterns are _not_ considered violations:
  
  <!-- prettier-ignore -->
  ```css
  a::pseudo-element {}
  ```
  
  <!-- prettier-ignore -->
  ```css
  a::my-pseudo {}
  ```
  
  <!-- prettier-ignore -->
  ```css
  a::my-other-pseudo {}
  ```
  