css - OOCSS Separation of Container and Content?

Question

Question: Is the second OOCSS principle really valid?

According to the OOCSS second principle you're not supposed to have location dependent styles:

Quote from https://github.com/stubbornella/oocss/wiki

Essentially, this means “rarely use location-dependent styles”. An object should look the same no matter where you put it. So instead of styling a specific h2 with .myObject h2 {...}, create and apply a class that describes the h2 in question, like h2 class="category".

Lets take a practical example of this. Say I have a standard 2.0 setup with a normal body (white background) and a huge footer (black background). In the body we have black links and in the footer of course we need white. Isn't the simplest and most intuitive way to achieve this simply to:

a{ color: #000; }
.footer a{ color: #FFF; }

If I where to follow OOCSS principles I'd have to first create a class:

.inverted{ color: #FFF; }

Then proceed to add that class to every link I want inverted. That seems like a hassle.

Isn't the purpose of the whole language that styles are made to Cascade? Am I misunderstanding something here?

Answer 1

I think you are right in the sense that yes, in your specific example.. perhaps doing it your way would be easier. But then again, if you look at the first sentence in the OOCSS page:

How do you scale CSS for thousands of pages?

In that context.. the second principle makes perfect sense.. so using your same example (ie let's assume we implemented your solution).. let's say that a year down the road your company decides to create light grey buttons in the black footer having black text:

<!-- inside footer -->
<a class="button lightGrey">link</a>

in this case.. all the a tags will be white because they're covered by your cascading. So then we will have to go create another sytle just to undo what your solution did:

.footer a.button.lightGrey {
   color: #000;  /* huh? but i thought we did this before with a {color: #000;} ?*/
}

where as if we simply made a decision that all a tags by default are black (see last note):

a{ color: #000; }

then in the footer we will create a special type of link that are supposed to be white:

.footerLinks { color: #FFF }

then a year later some of the links are still white.. others within the greyLight button will be black:

<a class="button lightGrey">link</a>

then here we don't have to worry about undoing anything.. a tags have a default color.. and that's it. if 2 years later someone decides that the links inside the lightGrey buttons (anywhere on the site, not only withen the footer.. which is the whole point of OOCSS) should be red.. then this would be the OOCSS approach:

.redLink {
 color: red;
}

and the html will be

<a class="button lightGrey redLink">link</a>

in this case it won't matter if we take out the .lightGrey class, or we can have this code within or not within a footer .. it's all the same.. it results in more predictable and re-usable code.. which is OOCSS (I'm very glad that they're finally formalising this.. thanks a lot for the post btw).

One last note: To be pure OOCSS, one shouldn't change the default color of a ie a {color: #000;} is wrong!, it should be left to it's default color (which is blue).. whenever anyone wants to change that color.. then they must specify it ie

<a class="redLink">..</a>

so in this case it's more like the default a is the parent class.. and everything else subclasses it and overrides its default behaviour..

update - response to comments:

reputable site argument:

such initiatives are almost always driven by the community then adopted by reputable companies.. and even when they are adopted by larger companies it usually happens from the bottom up through enthusiastic developers who advocate for such change.. I for one was such an advocate when I was working in Amazon. And even when it's adopted.. it's usually at a small scale and not across all units in the org. it wouldn't even be a good idea for the Googles and the Amazons and the facebooks etc to enforce such a rule b/c there will always be a difference of opinion.. not to mention that such micromanagement would constrain the engineer's creativity.. there could be a guideline in a wiki for a team (ie we had one for the Amazon Kindle Touch app store) but to enforce that rule across 10,000 engineers working across the company wouldn't be practical nor desirable.

So in short if you see value in OOCSS, and start implementing on your site, and advocating it to your fellow web devs, and then it becomes a trend, that's when it eventually becomes an industry wide best practice and that's when you can expect to see it on facebook etc.

example:

take a look at this:
simple: http://jsfiddle.net/64sBg/
a bit more detailed: http://jsfiddle.net/64sBg/2/

without going too much detail (I'm sure you will see the pattern) you can see that the granularity in css descriptions allows for subtle changes without any redundancy in style definition. So notice the left arrow vs right arrow.. also the .red and .blue styles can be subsequently applied to tables etc..

also notice that there isn't a single cascading in my css.. so my styles can be completely independently applied (ie implementing the rule An object should look the same no matter where you put it)

lastly.. there is still use for cascading.. you can definitely use it in your jQuery selectors for example.. also cascading happens by default (ie without you having to explicitly set it in your css styles).. so if you take look at the css below.. you will notice that the font properties of body has cascaded down to all the buttons.

<a class="button blue dark">
    <div class=" arrowDownWhite rightArrow">Analytics</div>
</a>

<a class="button red dark">
    <div class=" arrowDownWhite leftArrow">Actions</div>
</a>

<a class="button grey light">
    <div class=" arrowDownRed leftArrow">options</div>
</a>

and css:

body 
{
    font-family: Trebuchet MS,Liberation Sans,DejaVu Sans,sans-serif;
    font-size: 15pt;
}

.button 
{
    padding: .5em 1em;
    display: inline-block;
    text-decoration: none;
}
.dark {
    color: white;
}

.light{
    color: #E40E62;
}
.blue
{
    background-color: #51C8E8;
}
.red 
{
    background-color: #E40E62;
}
.grey 
{
    background-color: #E0E0E0 ;
}
.arrowDownWhite
{
    background-image:url(http://s2.postimage.org/ywam7ec4l/small_Arrow_Down_White.png); 
    background-repeat:no-repeat;

}

.arrowDownRed 
{
    background-image:url(http://s2.postimage.org/je5743t2d/small_Arrow_Down_Red.png);
    background-repeat:no-repeat;
}

.leftArrow 
{
    padding-left: 1em;
    background-position: left center;   
}

.rightArrow
{
    padding-right: 1em;
    background-position: right center;  
}