Object Oriented CSS

Graeme Blackwood Creative Lead, Deeson Online

deeson-online.co.uk @graemeblackwood

Props•Nicole Sullivan, http://www.stubbornella.org

•Jonathan Snook (SMACSS), http://smacss.com

•Everyone at http://thesassway.com

•Chris Eppstein, http://compass-style.org

•Kevin Poulton http://www.flickr.com/photos/kevinpoulton

•And loads more!

Before we get going

OO CSS !=OO Programming

But an OOP mindset can be applied to CSS

OOCSS does not require any newer technologies

It works in IE6 – no need for CSS3, HTML5 etc

Semantic markup is very helpful, but usually not essential

Semantic is better though!

The traditional approach to CSS

Style output as needed Each item / page individually...

Target styles by drilling down through nested elements

Problems with traditional CSS

Coding takes a lot longer

It gets bloated

It is difficult to read and hard to reuse

Traditional CSS is tough to maintain

‽

Object Oriented CSSA new way of thinking

Separate layout from theme(Use a grid system!)

Separate the container from the content

Look for shared stylesYou will see them everywhere

Why should I care?

Reusable code

Faster development

Less effort to code

Easier to maintain

Less code,smaller files

Getting started

Using a grid system?You are already on the right track!

Use a reset stylesheetHTML5 boilerplate’s normalize.css

Set good base stylesTo minimise later overrides

* {box-sizing: border-box} is pretty handy

Set good base stylesTo minimise later overridesBuild HTML prototypeswith Drupal in mind...

Clean up what Drupal throws at youDon’t just style,theme!

Lose unnecessary markup if it affects you

Some divs are totally pointless!

Don’t be too obsessed with perfect markup

Just enough is ok

“Now, this is just a simulation of what the blocks will look like once they’re assembled”

Let’s look at some real world applications...

.block = inherited base styles only

.grid-4 = grid class

.theme-a = theme class, H3 and p inherit colour

.padded is a class I add to the grid framework for situations like this

<div class=”grid-4 theme-a block”> <h3>Block title</h3> <p>Hello world!</p></div>

.grid-4 comes from your grid framework

.theme-a { background-color: #580174; border-radius: 6px; color: #fff; //H3 and p inherit this}

Carousel nav tabsObject is a Drupal menu – UL with a class of .sidebar-menu. Custom jQuery targets the ID.

Also used on a listingAnd it flexes to the container

99% of the styles are reused, targeted through .right .sidebar-menu only to flip the active item

Carousel itemsWith a class of .product-box

Reused on listing pages

Same layout as product listings and carousel, flexed to image size

What aboutSASS and LESS?Why bother with presentational classes in markup anymore?

Not everyone wants to use a CSS preprocessorAnd the mindset of reduce, reuse & recycle is just as important even with one

Use SASS wisely – it’s another layer to debug

Be particularly careful with nested selectors http://thesassway.com/beginner/the-inception-rule

http://37signals.com/svn/posts/3003-css-taking-control-of-the-cascade

Disregarding the other principles of OOCSS may create pain laterYou could end up with generated CSS bloated even more than if you had hand-coded it

Summary•OOCSS is as much a mindset as a technique

•The principles are to reduce, reuse and recycle code

•This is done through separating layout from theme

•and the container from the content

•It relies primarily on reused classes and markup

•We are working on Drupal 8 to make it much easier to change markup. In the meantime, try Display Suite or Skinr for node theming

Summary

•CSS preprocessors like SASS and LESS are great

•But they create another layer to debug

•And the code they generate can be very bloated

•Preprocessors are not an excuse to be lazy

•They still need to be used with an OO mindset

@graemeblackwood

Questions?

Thanks for listening!

Most of the fantastic lego images were by Kevin Poulton http://www.flickr.com/photos/kevinpoulton