</^[^.]+$|\.(?!(css|gif|ico|jpg|js|png|txt|svg|woff|ttf|map|json)$)([^.]+$)/> code example

Example 1: css

/* Answer to "css" */

/*
  Cascading Style Sheets (CSS) is a style sheet language used for
  describing the presentation of a document written in a
  markup language like HTML.

  In other words, it's the style of the website.

  For example, the positioning of everything on a website or
  the colour, shape, size of a button. Every design on a
  website is most likely made using css.
*/

Example 2: css

CSS implies Cascading Style Sheet. In a webpage, the HTML codes
gives the structure or the data or the information  While CSS is used to make the
data designable , stylize , etc.  to  attract the traffic or the clients  in a 
website. There are many more programming languages used for the design.
The latest version of CSS is CSS3.