CSS can be validated similar to HTML by CSS validator tool (http://jigsaw.w3.org/css-validator/)
provided by W3C by typing the URL of a web page (or the address to an external CSS file), or uploading a CSS file or copy and pasting CSS code into a web form and submit it for validation.
provided by W3C by typing the URL of a web page (or the address to an external CSS file), or uploading a CSS file or copy and pasting CSS code into a web form and submit it for validation.
Web browsers also have built-in error checking tools for examining CSS like in Mozilla Firefox click Error Console option in Tools menu to open CSS errors.
It is shown in the figure.