Is It Time for a Rethink? – A Listing 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 growing your CSS mobile-first must also be nice, too…proper? 

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Effectively, not essentially. Traditional mobile-first CSS growth is predicated 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 a superb 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 initiatives, mobile-first CSS could but be the perfect instrument for the job, however first you have to consider simply how applicable 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 have to look ahead to, and I’ll talk about some alternate options if mobile-first doesn’t appear to fit your challenge.

Benefits of mobile-first#section2

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

Improvement hierarchy. One factor you undoubtedly get from mobile-first is a pleasant growth hierarchy—you simply concentrate on the cell view and get growing. 

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

Prioritizes the cell view. The cell view is the easiest and arguably a very powerful, because it encompasses all the important thing person journeys, and sometimes accounts for a larger proportion of person visits (relying on the challenge). 

Prevents desktop-centric growth. As growth is finished utilizing desktop computer systems, it may be tempting to initially concentrate on the desktop view. However desirous about cell from the beginning prevents us from getting caught afterward; nobody desires to spend their time retrofitting a desktop-centric website to work on cell units!

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. 

Increased CSS specificity. Types which have been reverted to their browser default worth in a category identify declaration now have a better specificity. This is usually a headache on massive initiatives once 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, basic 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 may be nothing inherently fallacious with overwriting values; CSS was designed to just do that. Nonetheless, inheriting incorrect values is unhelpful and will be burdensome and inefficient. It may well additionally result in elevated fashion specificity when you must overwrite kinds to reset them again to their defaults, one thing that will trigger points afterward, particularly in case you are utilizing a mixture of bespoke CSS and utility courses. We gained’t be capable of use a utility class for a method that has been reset with a better specificity.

With this in thoughts, I’m growing CSS with a concentrate on the default values rather more lately. Since there’s no particular order, and no chains of particular values to maintain monitor of, this frees me to develop breakpoints concurrently. I consider discovering widespread 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 may have a look at every breakpoint as a clear slate. If a element’s structure seems to be prefer it ought to be based mostly on Flexbox in any respect breakpoints, it’s effective and will be coded within the default fashion sheet. But when it seems to be like Grid could be significantly better for giant screens and Flexbox for cell, these can each be achieved fully independently when the CSS is put into closed media question ranges. Additionally, growing concurrently requires you to have a superb understanding of any given element in all breakpoints up entrance. This may 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 posh element for cell, after which get the designs for desktop and discover they’re equally advanced and incompatible with the HTML we created for the cell view! 

Although this strategy isn’t going to swimsuit everybody, I encourage you to provide it a strive. There are many instruments on the market to assist with concurrent growth, corresponding 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 cell view, have a superb understanding of the necessities for different breakpoints, and like to work on one machine at a time, then by all means follow the basic growth order. The essential factor is to establish widespread kinds and exceptions so you may put them within the related stylesheet—a form of guide tree-shaking course of! Personally, I discover this a bit of simpler when engaged on a element throughout breakpoints, however that’s in no way a requirement.

Closed media question ranges in follow #section5

In basic mobile-first CSS we overwrite the kinds, however we will keep away from this by utilizing media question ranges. For 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.

Traditional 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 refined distinction is that the mobile-first instance units the default padding to “20px” after which overwrites it at every breakpoint, setting it 3 times in complete. 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 aim is to: 

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

To this finish, closed media question ranges are our greatest good friend. 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 more likely to introduce undesirable alterations, and our regression testing solely must concentrate on the breakpoint we have now truly 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 might do that by setting the cell 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 want with mobile-first), we will wrap the cell padding in a closed media question (since it’s now additionally an exception) so it gained’t get picked up at wider breakpoints. On the desktop breakpoint, we gained’t have to set any padding fashion, as we would like the browser default worth.

Bundling versus separating the CSS#section6

Again within the day, retaining the variety of requests to a minimal was essential because of the browser’s restrict of concurrent requests (sometimes 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 now not the massive deal it was. This enables us to separate the CSS into a number of recordsdata by media question. The clear advantage of that is the browser can now request the CSS it presently wants with a better precedence than the CSS it doesn’t. That is extra performant and might scale 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. 

Observe: 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 test the Protocol column.

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

Additionally, in case your website remains to be utilizing HTTP/1…WHY?!! What are you ready for? There may be wonderful person assist for HTTP/2.

Separating the CSS into particular person recordsdata is a worthwhile job. 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 will be deferred. Primarily based on this, it allocates every file an applicable precedence.

Within the following instance of a web site visited on a cell breakpoint, we will see the cell and default CSS are loaded with “Highest” precedence, as they’re presently 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 completely different recordsdata linked and marked up with the related media attribute, the browser can prioritize the recordsdata it presently wants. Utilizing closed media question ranges permits the browser to do that in any respect widths, versus basic mobile-first min-width queries, the place the desktop browser must obtain all of the CSS with Highest precedence. We are able to’t assume that desktop customers all the time have a quick connection. As an illustration, in lots of rural areas, web connection speeds are nonetheless gradual. 

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

Bundled CSS

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

This single file comprises all of the CSS, together with all media queries, and it is going to be downloaded with Highest precedence.

Separated CSS

<hyperlink href="" rel="stylesheet"><hyperlink href="cell.css" media="display screen and (max-width: 767.98px)" rel="stylesheet"><hyperlink href="pill.css" media="display screen and (min-width: 768px) and (max-width: 1083.98px)" rel="stylesheet"><hyperlink href="desktop.css" media="display screen 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 presently wants. Out of the 5 recordsdata listed above, two will probably be downloaded with Highest precedence: the default file, and the file that matches the present media question. The others will probably be downloaded with Lowest precedence.

Relying on the challenge’s deployment technique, a change to at least one file (cell.css, for instance) would solely require the QA crew to regression check on units in that particular media question vary. Examine that to the prospect of deploying the only bundled website.css file, an strategy that may usually set off a full regression check.

The uptake of mobile-first CSS was a extremely essential milestone in internet growth; it has helped front-end builders concentrate on cell internet purposes, quite than growing websites on desktop after which making an attempt to retrofit them to work on different units.

I don’t suppose anybody desires to return to that growth mannequin once more, but it surely’s essential we don’t lose sight of the problem it highlighted: that issues can simply get convoluted and fewer environment friendly if we prioritize one specific machine—any machine—over others. For that reason, specializing in the CSS in its personal proper, all the time aware of what’s the default setting and what’s an exception, looks like 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 also be a bit extra simplified and productive. 

On the whole, simplifying CSS rule creation each time we will is in the end a cleaner strategy than going round in circles of overrides. However whichever methodology you select, it must swimsuit the challenge. Cell-first could—or could not—change into the only option for what’s concerned, however first you have to solidly perceive the trade-offs you’re moving into.


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