gistfile1.el

; Display CSS Hexadecimal color values
; as background to that value.
(defvar hexcolour-keywords
'(("#[abcdef[:digit:]]\\{6\\}"
   (0 (put-text-property
       (match-beginning 0)
       (match-end 0)
       'face (list :background 
                   (match-string-no-properties 0)))))))

(defun hexcolour-add-to-font-lock ()
(font-lock-add-keywords nil hexcolour-keywords))

(add-hook 'css-mode-hook 'hexcolour-add-to-font-lock)