Why is my CSS style not being applied?

Have you tried forcing the selectors to be in the front of the class?

p span label.fancify {

    font-size: 1.5em;
    font-weight: 800;
    font-family: Consolas, "Segoe UI", Calibri, sans-serif;
    font-style: italic;
}

Usually it will add more weight to your CSS declaration. My mistake ... There should be no space between the selector and the class. The same goes for the ID. If you have for example:

<div id="first">
    <p id="myParagraph">Hello <span class="bolder">World</span></p>
</div>

You would style it like this:

div#first p#myParagraph {
     color : #ff0000;
}

Just to make a complete example using a class:

div#first p#myParagraph span.bolder{
    font-weight:900;
}

For more information about pseudo-selectors and child selectors : http://www.w3.org/TR/CSS2/selector.html

CSS is a whole science :) Beware that some browsers can have incompatibilities and will not show you the proper results. For more information check this site: http://www.caniuse.com/

There could be an error earlier in the CSS file that is causing your (correct) CSS to not work.

Posting, since it might be useful for someone in the future:

For me, when I got here, the solution was browser cache. Had to hard refresh Chrome (cmd/ctrl+shift+R) to get the new styles applied, it seems the old ones got cached really "deep".

This question/answer might come in handy for someone. And hard refresh tips for different browsers for those who don't use Chrome.

I was going out of my mind when a rule was being ignored while others weren't. Run your CSS through a validator and look for parsing errors.

I accidentally used // for a comment instead of /* */ causing odd behavior. My IDE said nothing about it. I hope it helps someone.