Is It Time for a Rethink? – A Checklist Aside

The mobile-first design methodology is nice—it focuses on what actually issues to the person, it’s well-practiced, and it’s been a typical design sample for years. So creating your CSS mobile-first also needs to be nice, too…proper? 

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Effectively, not essentially. Basic mobile-first CSS growth relies on the precept of overwriting fashion declarations: you start your CSS with default fashion declarations, and overwrite and/or add new kinds as you add breakpoints with min-width media queries for bigger viewports (for overview see “What’s Cell First CSS and Why Does It Rock?”). However all these exceptions create complexity and inefficiency, which in flip can result in an elevated testing effort and a code base that’s more durable to keep up. Admit it—how many people willingly need that?

By yourself tasks, mobile-first CSS could but be the most effective software for the job, however first you must consider simply how acceptable it’s in mild of the visible design and person interactions you’re engaged on. That will help you get began, right here’s how I am going about tackling the components you must look ahead to, and I’ll talk about some alternate options if mobile-first doesn’t appear to fit your venture.

Benefits of mobile-first#section2

A number of the issues to love with mobile-first CSS growth—and why it’s been the de facto growth methodology for thus lengthy—make a variety of sense:

Growth hierarchy. One factor you undoubtedly get from mobile-first is a pleasant growth hierarchy—you simply concentrate on the cellular view and get creating. 

Tried and examined. It’s a tried and examined methodology that’s labored for years for a motive: it solves an issue rather well.

Prioritizes the cellular view. The cellular view is the easiest and arguably crucial, because it encompasses all the important thing person journeys, and infrequently accounts for a larger proportion of person visits (relying on the venture). 

Prevents desktop-centric growth. As growth is completed utilizing desktop computer systems, it may be tempting to initially concentrate on the desktop view. However desirous about cellular from the beginning prevents us from getting caught in a while; nobody needs to spend their time retrofitting a desktop-centric website to work on cellular gadgets!

Disadvantages of mobile-first#section3

Setting fashion declarations after which overwriting them at larger breakpoints can result in undesirable ramifications:

Extra complexity. The farther up the breakpoint hierarchy you go, the extra pointless code you inherit from decrease breakpoints. 

Larger CSS specificity. Types which were reverted to their browser default worth in a category identify declaration now have a better specificity. This generally is a headache on massive tasks while you need to preserve the CSS selectors so simple as attainable.

Requires extra regression testing. Modifications to the CSS at a decrease view (like including a brand new fashion) requires all larger breakpoints to be regression examined.

The browser can’t prioritize CSS downloads. At wider breakpoints, traditional mobile-first min-width media queries don’t leverage the browser’s functionality to obtain CSS recordsdata in precedence order.

The issue of property worth overrides#section4

There’s nothing inherently flawed with overwriting values; CSS was designed to just do that. Nonetheless, inheriting incorrect values is unhelpful and may be burdensome and inefficient. It might additionally result in elevated fashion specificity when it’s important to overwrite kinds to reset them again to their defaults, one thing which will trigger points in a while, particularly if you’re utilizing a mixture of bespoke CSS and utility courses. We received’t be capable to use a utility class for a method that has been reset with a better specificity.

With this in thoughts, I’m creating CSS with a concentrate on the default values far more nowadays. Since there’s no particular order, and no chains of particular values to maintain observe of, this frees me to develop breakpoints concurrently. I think about discovering frequent kinds and isolating the particular exceptions in closed media question ranges (that’s, any vary with a max-width set). 

This strategy opens up some alternatives, as you’ll be able to take a look at every breakpoint as a clear slate. If a part’s format seems prefer it ought to be primarily based on Flexbox in any respect breakpoints, it’s positive and may be coded within the default fashion sheet. But when it seems like Grid can be a lot better for big screens and Flexbox for cellular, these can each be executed completely independently when the CSS is put into closed media question ranges. Additionally, creating concurrently requires you to have understanding of any given part in all breakpoints up entrance. This might help floor points within the design earlier within the growth course of. We don’t need to get caught down a rabbit gap constructing a fancy part for cellular, after which get the designs for desktop and discover they’re equally complicated and incompatible with the HTML we created for the cellular view! 

Although this strategy isn’t going to go well with everybody, I encourage you to present it a strive. There are many instruments on the market to assist with concurrent growth, equivalent to Responsively App, Blisk, and lots of others. 

Having mentioned that, I don’t really feel the order itself is especially related. In case you are snug with specializing in the cellular view, have understanding of the necessities for different breakpoints, and like to work on one system at a time, then by all means follow the traditional growth order. The essential factor is to establish frequent kinds and exceptions so you’ll be able to put them within the related stylesheet—a kind of handbook tree-shaking course of! Personally, I discover this slightly simpler when engaged on a part throughout breakpoints, however that’s under no circumstances a requirement.

Closed media question ranges in follow #section5

In traditional mobile-first CSS we overwrite the kinds, however we are able to keep away from this through the use of media question ranges. As an instance the distinction (I’m utilizing SCSS for brevity), let’s assume there are three visible designs: 

  • smaller than 768
  • from 768 to under 1024
  • 1024 and something bigger 

Take a easy instance the place a block-level ingredient has a default padding of “20px,” which is overwritten at pill to be “40px” and set again to “20px” on desktop.

Basic min-width mobile-first

.my-block {
  padding: 20px;
  @media (min-width: 768px) {
    padding: 40px;
  @media (min-width: 1024px) {
    padding: 20px;

Closed media question vary

.my-block {
  padding: 20px;
  @media (min-width: 768px) and (max-width: 1023.98px) {
    padding: 40px;

The delicate distinction is that the mobile-first instance units the default padding to “20px” after which overwrites it at every breakpoint, setting it thrice in whole. In distinction, the second instance units the default padding to “20px” and solely overrides it on the related breakpoint the place it isn’t the default worth (on this occasion, pill is the exception).

The objective is to: 

  • Solely set kinds when wanted. 
  • Not set them with the expectation of overwriting them in a while, repeatedly. 

To this finish, closed media question ranges are our greatest buddy. If we have to make a change to any given view, we make it within the CSS media question vary that applies to the particular breakpoint. We’ll be a lot much less prone to introduce undesirable alterations, and our regression testing solely must concentrate on the breakpoint we’ve got really edited. 

Taking the above instance, if we discover that .my-block spacing on desktop is already accounted for by the margin at that breakpoint, and since we need to take away the padding altogether, we may do that by setting the cellular padding in a closed media question vary.

.my-block {
  @media (max-width: 767.98px) {
    padding: 20px;
  @media (min-width: 768px) and (max-width: 1023.98px) {
    padding: 40px;

The browser default padding for our block is “0,” so as an alternative of including a desktop media question and utilizing unset or “0” for the padding worth (which we would wish with mobile-first), we are able to wrap the cellular padding in a closed media question (since it’s now additionally an exception) so it received’t get picked up at wider breakpoints. On the desktop breakpoint, we received’t must set any padding fashion, as we would like the browser default worth.

Bundling versus separating the CSS#section6

Again within the day, maintaining the variety of requests to a minimal was crucial as a result of browser’s restrict of concurrent requests (usually round six). As a consequence, using picture sprites and CSS bundling was the norm, with all of the CSS being downloaded in a single go, as one stylesheet with highest precedence. 

With HTTP/2 and HTTP/3 now on the scene, the variety of requests is not the large deal it was. This enables us to separate the CSS into a number of recordsdata by media question. The clear good thing about that is the browser can now request the CSS it at the moment wants with a better precedence than the CSS it doesn’t. That is extra performant and might cut back the general time web page rendering is blocked.

Which HTTP model are you utilizing?#section7

To find out which model of HTTP you’re utilizing, go to your web site and open your browser’s dev instruments. Subsequent, choose the Community tab and ensure the Protocol column is seen. If “h2” is listed underneath Protocol, it means HTTP/2 is getting used. 

Be aware: to view the Protocol in your browser’s dev instruments, go to the Community tab, reload your web page, right-click any column header (e.g., Title), and verify the Protocol column.

Chrome dev tools, Network tab filtered by document, Protocol column
Be aware: for a summarized comparability, see ImageKit’s “HTTP/2 vs. HTTP/1.”

Additionally, in case your website continues to be utilizing HTTP/1…WHY?!! What are you ready for? There’s wonderful person help for HTTP/2.

Separating the CSS into particular person recordsdata is a worthwhile process. Linking the separate CSS recordsdata utilizing the related media attribute permits the browser to establish which recordsdata are wanted instantly (as a result of they’re render-blocking) and which may be deferred. Primarily based on this, it allocates every file an acceptable precedence.

Within the following instance of an internet site visited on a cellular breakpoint, we are able to see the cellular and default CSS are loaded with “Highest” precedence, as they’re at the moment wanted to render the web page. The remaining CSS recordsdata (print, pill, and desktop) are nonetheless downloaded in case they’ll be wanted later, however with “Lowest” precedence. 

Chrome dev tools, Network tab filtered by css, Priority column

With bundled CSS, the browser must obtain the CSS file and parse it earlier than rendering can begin.

Whereas, as famous, with the CSS separated into totally different recordsdata linked and marked up with the related media attribute, the browser can prioritize the recordsdata it at the moment wants. Utilizing closed media question ranges permits the browser to do that in any respect widths, versus traditional mobile-first min-width queries, the place the desktop browser must obtain all of the CSS with Highest precedence. We will’t assume that desktop customers at all times have a quick connection. For example, in lots of rural areas, web connection speeds are nonetheless sluggish. 

The media queries and variety of separate CSS recordsdata will fluctuate from venture to venture primarily based on venture necessities, however would possibly look much like the instance under.

Bundled CSS

<hyperlink href="" rel="stylesheet">

This single file accommodates all of the CSS, together with all media queries, and will probably be downloaded with Highest precedence.

Separated CSS

<hyperlink href="" rel="stylesheet"><hyperlink href="cellular.css" media="display and (max-width: 767.98px)" rel="stylesheet"><hyperlink href="pill.css" media="display and (min-width: 768px) and (max-width: 1083.98px)" rel="stylesheet"><hyperlink href="desktop.css" media="display and (min-width: 1084px)" rel="stylesheet"><hyperlink href="print.css" media="print" rel="stylesheet">

Separating the CSS and specifying a media attribute worth on every hyperlink tag permits the browser to prioritize what it at the moment wants. Out of the 5 recordsdata listed above, two shall be downloaded with Highest precedence: the default file, and the file that matches the present media question. The others shall be downloaded with Lowest precedence.

Relying on the venture’s deployment technique, a change to 1 file (cellular.css, for instance) would solely require the QA workforce to regression take a look at on gadgets in that particular media question vary. Examine that to the prospect of deploying the only bundled website.css file, an strategy that might usually set off a full regression take a look at.

The uptake of mobile-first CSS was a very essential milestone in net growth; it has helped front-end builders concentrate on cellular net purposes, moderately than creating websites on desktop after which making an attempt to retrofit them to work on different gadgets.

I don’t assume anybody needs to return to that growth mannequin once more, nevertheless it’s essential we don’t lose sight of the difficulty it highlighted: that issues can simply get convoluted and fewer environment friendly if we prioritize one explicit system—any system—over others. For that reason, specializing in the CSS in its personal proper, at all times conscious of what’s the default setting and what’s an exception, looks as if the pure subsequent step. I’ve began noticing small simplifications in my very own CSS, in addition to different builders’, and that testing and upkeep work can be a bit extra simplified and productive. 

Normally, simplifying CSS rule creation each time we are able to is in the end a cleaner strategy than going round in circles of overrides. However whichever methodology you select, it must go well with the venture. Cell-first could—or could not—turn into your best option for what’s concerned, however first you must solidly perceive the trade-offs you’re moving into.

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