CSS Intelligence: Speculating On The Future Of A Smarter Language — Smashing Magazine

Gabriel is a front-end developer and technical writer. He specializes in HTML, CSS, JavaScript, React, Vue, TailwindCSS, and BootStrap, with a track record of … More about Gabriel ↬
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Once upon a time, CSS was purely presentational. It imperatively handled the fonts, colors, backgrounds, spacing, and layouts, among other styles, for markup languages. It was a language for looks, doing what it was asked to, never thinking or making decisions. At least, that was what it was made for when Håkon Wium Lie proposed CSS in 1994, and the World Wide Web Consortium (W3C) adopted it two years later.
Fast-forward to today, a lot has changed with the addition of new features, and more are on the way that shift the style language to a more imperative paradigm. CSS now actively powers complex responsive and interactive user interfaces. With recent advancements like container queries, relational pseudo-classes, and the if() function, the language once within the domains of presentations has stepped foot into the territory of logic, reducing its reliance on the language that had handled its logical aspect to date, JavaScript.
This shift presents interesting questions about CSS and its future for developers. CSS has deliberately remained within the domains of styling alone for a while now, but is it time for that to change? Also, is CSS still a presentational language as it started, or is it becoming something more and bigger? This article explores how smart CSS has become over the years, where it is heading, the problems it is solving, whether it is getting too complex, and how developers are reacting to this shift.
A glimpse into CSS history shows a language born to separate content from presentation, making web pages easier to manage and maintain. The first official version of CSS, CSS1, was released in 1996, and it introduced basic styling capabilities like font properties, colors, box model (padding, margin, and border), sizes (width and height), a few simple displays (none, block, and inline), and basic selectors.
Two years later, CSS2 was launched and expanded what CSS could style in HTML with features like positioning, z-index, enhanced selectors, table layouts, and media types for different devices. However, there were inconsistencies within the style language, an issue CSS2.1 resolved in 2011, becoming the standard for modern CSS. It simplified web authoring and site maintenance.
CSS was largely static and declarative during the years between CSS1 and CSS2.1. Developers experienced a mix of frustrations and breakthroughs for their projects. Due to the absence of intuitive layouts like Flexbox and CSS Grid, developers relied on hacky alternatives with table layouts, positioning, or floats to get around complex designs, even though floats were originally designed for text to wrap around an obstacle on a webpage, usually a media object. As a result, developers faced issues with collapsing containers and unexpected wrapping behaviour. Notwithstanding, basic styling was intuitive. A newbie could easily pick up web development today and add basic styling the next day. CSS was separated from content and logic, and as a result, it was highly performant and lightweight.
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Things changed when CSS3 rolled out. Developers had expected a single monolithic update like the previous versions, but their expectations and the reality of the latest release were unmatched. The CSS3 red carpet revealed a modular system with powerful layout tools like Flexbox, CSS Grid, and media queries, defining for the first time how developers establish responsive designs. With over 20 modules, CSS3 marked the inception of a “smarter CSS”.
Flexbox’s introduction around 2012 provided a flexible, one-dimensional layout system, while CSS Grid, launched in 2017, took layout a step further by offering a two-dimensional layout framework, making complex designs with minimal code possible. These advancements, as discussed by Chris Coyier, reduced reliance on hacks like floats.
It did not stop there. There’s media queries, a prominent release of CSS3, that is one of the major contributors to this smart CSS. With media queries, CSS can react to different devices’ screens, adjusting its styles to fit the screen dimensions, aspect ratio, and orientation, a feat that earlier versions could not easily achieve. In the fifth level, it added user preference media features such as prefers-color-scheme and prefers-reduced-motion, making CSS more user-centric by adapting styles to user settings, enhancing accessibility.
CSS3 marked the beginning of a context-aware CSS.
In web development, the term “context-awareness” has always been used with components, but what drives a context-aware component? If you mentioned anything other than the component’s styles, you would be wrong! For a component to be considered context-aware, it needs to feel its environment’s presence and know what happens in it. For instance, for your website to update its styles to accommodate a dark mode interface, it needs to be aware of the user’s preferences. Also, to change its layout, a website needs to know the device a user is accessing it on — and thanks to user preference media queries, that is possible.
Despite these features, CSS remained largely reactive. It responded to external factors like screen size (via media queries) or input states (like :hover, :focus, or :checked), but it never made decisions based on the changes in its environment. Developers typically turn to JavaScript for that level of interaction.
However, not anymore.
For example, with container queries and, more recently, container style queries, CSS now responds not only to layout constraints but to design intent. It can adjust based on a component’s environment and even its