Concept idea: Connect HTML tags into my CSS file

Basically what I want is that when you have your HTML file with <link> tag connected to your CSS I want to see the tags that have not been declared in the css but are in HTML.

for example:
...
<img class="whateverClassYouCanImagine" src="myLinkIsHere.png">

...

and when I type this into css:
img.

I would like to see list of all img tags that have a class but have not been set any attributes in css.