Great list. Thanks for this.

As for variables // I tend to use a general class for colors and utilize this inside the HTML file.

Specifically speaking —

CSS:
.politics {background:#d90000;color:#fff;}
.sports {background:#430000;color:#fff;}

.header {width:100%;height:140px;}

HTML:
<div class=“header politics”>
NEWS
</div>

<div class=“header sports”>
SPORTS
</div>

This way I make use of the URL by dynamically parsing elements into the class attribute. Which is not possible to do inside the CSS file.

In other words:
<div class=“header {segment_1}”>
SPORTS
</div>

Where {segment_1} would be /SPORTS/ right after http://domain.com/

(BTW Expression Engine is my weapon of choice)

This works for me quite nicely, and I can change selector values very easily.

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Cheers for the great post and your awesome wish-list : )

Valon.
boldUnderline.