A list of all CSSLint settings with descriptions

CSSLint - All Settings.js

{
  //  Don't use adjoining classes (.foo.bar)
  "adjoining-classes": "warning",

  // Don't use width or height when using padding or border. 
  "box-model": true,

  // box-sizing doesn't work in IE6 and IE7.
  "box-sizing": "warning",

  // Use the bulletproof @font-face syntax to avoid 404's in old IE
  "bulletproof-font-face": true,

  // Include all compatible vendor prefixes to reach a wider
  "compatible-vendor-prefixes": "warning",

  /*
   * Rule: Certain properties don't play well with certain display values. 
   * - float should not be used with inline-block
   * - height, width, margin-top, margin-bottom, float should not be used with inline
   * - vertical-align should not be used with block
   * - margin, float should not be used with table-*
   */
  "display-property-grouping": true,

  // Disallow duplicate background-images (using url)
  "duplicate-background-images": "warning",

  /* Duplicate properties must appear one after the other If an already-defined property
   *appears somewhere else in the rule, then it's likely an error.
   */
  "duplicate-properties": true,

  // Style rules without any properties defined should be removed.
  "empty-rules": true,

  // There should be no syntax errors
  "errors": true,

  // Fallback colours 
  "fallback-colors": "warning",

  // You shouldn't use more than 10 floats. If you do, there's probably room for some abstraction.
  "floats": "warning",

  // Avoid too many @font-face declarations in the same stylesheet
  "font-faces": "warning",

  // You shouldn't need more than 9 font-size declarations
  "font-sizes": "warning",

  // When using a vendor-prefixed gradient, make sure to use them all
  "gradients": "warning",

  // Don't use IDs for selectors
  "ids": "warning",

  // Don't use @import, use <link> instead
  "import": "warning",

  // Make sure !important is not overused
  "important": "warning",

  // Properties should be known (listed in CSS3 specification) or be a vendor-prefixed property
  "known-properties": true,

  // outline: none or outline: 0 should only be used in a :focus rule
  "outline-none": "warning",

  // Don't use classes or IDs with elements
  "overqualified-elements": "warning",

  // Headings (h1-h6) should not be qualified (namespaced)
  "qualified-headings": "warning",

  // Selectors that look like regular expressions are slow and should be avoided
  "regex-selectors": "warning",

  // otal number of rules should not exceed x
  "rules-count": "warning",

  // Warn people with approaching the IE 4095 limit
  "selector-max-approaching": false,

  // Warn people past the IE 4095 limit 
  "selector-max": false,

  // Use shorthand properties where possible
  "shorthand": "warning",

  // Don't use properties with a star prefix
  "star-property-hack": "warning",

  // Don't use text-indent for image replacement if you need to support rtl
  "text-indent": "warning",

  // Don't use properties with a underscore prefix
  "underscore-property-hack": "warning",

  //  Headings (h1-h6) should be defined only once
  "unique-headings": "warning",

  // Don't use universal selector because it's slow
  "universal-selector": "warning",

  // Don't use unqualified attribute selectors because they're just like universal selectors
  "unqualified-attributes": false,

  // When using a vendor-prefixed property, make sure to include the standard one
  "vendor-prefix": true,

  // You don't need to specify units when a value is 0
  "zero-units": "warning"
}