If you have been involved with online marketing, then you will have been exposed to CSS. With or without you knowing it. So what is it?
Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation semantics of a document written in a mark-up language. Its most common application is to style web pages written in HTML. In plain English, it’s a set of rules that guide the look and formatting of a web page.
CSS is designed primarily to enable the separation of the content from the presentation, including elements such as the layout, colours, and fonts. This separation can:
- Improve content accessibility
- Provide more flexibility and control in the specification of presentation characteristics
- Enable multiple pages to share formatting
- Reduce complexity and repetition in the structural content
- Allow different styles for different rendering methods, such as on-screen, in print, by voice and on Braille-based, tactile devices and adjust to screen size or device
CSS specifies a priority scheme to determine which style rules apply if more than one rule matches against a particular element. In this so-called cascade, priorities or weights are calculated and assigned to rules, so that the results are predictable.
CSS has grown and evolved over the years from CSS 2, which is essentially a large single specification defining various features. CSS 3 is divided into several separate documents called “modules”. Each module adds new capabilities or extends features defined in CSS 2, rather than having to adjust the code for backward compatibility. Work on CSS level 3 started around the time of publication of the original CSS 2 recommendation. The earliest CSS 3 drafts were published in June 1999.
Due to the modularisation, different modules have different stability and statuses. As of June 2012, there are over fifty CSS modules published from the CSS Working Group, and some of these have been published as formal recommendations for areas such as Media Queries, Namespaces, Selectors Level 3 and Colour.
From an overall online perspective, CSS 3 is of great use for web designers and programmers alike. It helps control and standardise the look of a web page to ensure consistency across multiple browsers. From an email marketing point of view, there are mainly three reasons that limits the use.
- Partial support; it is not a given that a property will display consistently across different browsers/platforms for an email client. In some cases, the property does display, but the email client is interpreting it different from what’s intended.
- The property is stripped by the email client; some email clients simply disable CSS properties.
- Not supported by browser; web email clients across the browsers Firefox, Safari and Internet Explorer for instance selectively displays CSS 3 properties. The properties that are experimental implementations are tagged as such and may be permanently added to the browser’s rendering engine later on.
In essence, CSS3 is a long way from being accepted as standard in all web browsers or email clients. Strangely enough, mobile email clients are quickly adopting CSS 3 and render fairly well across most platforms.
It is important to bear in mind that CSS 3 is first and foremost being developed for the web, it may be a while before we discover practical applications in email for properties.
Ultimately, the decision to use CSS3 should be based on how many of your subscribers will be able to view your CSS 3 masterpiece, which can be determined in many instances by using the reports within your email broadcast system.
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