Is It Time for a Rethink? – A Record Aside


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

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Effectively, not essentially. Basic mobile-first CSS growth is predicated on the precept of overwriting type declarations: you start your CSS with default type declarations, and overwrite and/or add new types as you add breakpoints with min-width media queries for bigger viewports (for a very good overview see “What’s Cellular 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 take care of. Admit it—how many people willingly need that?

By yourself initiatives, mobile-first CSS could but be the very best instrument for the job, however first you could consider simply how acceptable it’s in gentle of the visible design and consumer interactions you’re engaged on. That can assist you get began, right here’s how I’m going about tackling the components you could 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 therefore lengthy—make a variety of sense:

Growth hierarchy. One factor you undoubtedly get from mobile-first is a pleasant growth hierarchy—you simply give attention to the cell 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 very well.

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

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

Disadvantages of mobile-first#section3

Setting type declarations after which overwriting them at greater 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 title declaration now have a better specificity. This is usually a headache on massive initiatives while you need to preserve the CSS selectors so simple as doable.

Requires extra regression testing. Modifications to the CSS at a decrease view (like including a brand new type) requires all greater 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 mistaken with overwriting values; CSS was designed to just do that. Nonetheless, inheriting incorrect values is unhelpful and will be burdensome and inefficient. It might probably additionally result in elevated type specificity when it’s a must to overwrite types to reset them again to their defaults, one thing that will trigger points in a while, particularly if you’re utilizing a mixture of bespoke CSS and utility lessons. We gained’t be capable to use a utility class for a mode that has been reset with a better specificity.

With this in thoughts, I’m creating CSS with a give attention to the default values rather 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 widespread types and isolating the precise exceptions in closed media question ranges (that’s, any vary with a max-width set). 

This method opens up some alternatives, as you may take a look at every breakpoint as a clear slate. If a element’s format seems to be prefer it needs to be primarily based on Flexbox in any respect breakpoints, it’s effective and will be coded within the default type sheet. But when it seems to be like Grid can be a lot better for giant screens and Flexbox for cell, these can each be performed completely independently when the CSS is put into closed media question ranges. Additionally, creating concurrently requires you to have a very good understanding of any given element 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 element for cell, after which get the designs for desktop and discover they’re equally complicated and incompatible with the HTML we created for the cell view! 

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

Having stated 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 very good understanding of the necessities for different breakpoints, and like to work on one machine at a time, then by all means keep on with the basic growth order. The essential factor is to determine widespread types and exceptions so you may put them within the related stylesheet—a type of handbook tree-shaking course of! Personally, I discover this just a little simpler when engaged on a element throughout breakpoints, however that’s in no way a requirement.

Closed media question ranges in observe #section5

In basic mobile-first CSS we overwrite the types, however we are able to keep away from this by utilizing media question ranges. For example 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 component 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 purpose is to: 

  • Solely set types when wanted. 
  • Not set them with the expectation of overwriting them in a while, many times. 

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 precise breakpoint. We’ll be a lot much less prone to introduce undesirable alterations, and our regression testing solely must give attention to the breakpoint we now have 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 a substitute of including a desktop media question and utilizing unset or “0” for the padding worth (which we would want with mobile-first), we are able to 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 type, as we wish 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 (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 not the large deal it was once. 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 at the moment 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 beneath 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., Identify), and examine 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 web site remains to be utilizing HTTP/1…WHY?!! What are you ready for? There may be wonderful consumer 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 determine 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 acceptable precedence.

Within the following instance of a web site visited on a cell breakpoint, we are able to see the cell 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 basic 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 all the time have a quick connection. As an example, in lots of rural areas, web connection speeds are nonetheless gradual. 

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

Bundled CSS

<hyperlink href=" site.css" rel="stylesheet">

This single file comprises all of the CSS, together with all media queries, and it will likely 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 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 at least one file (cell.css, for instance) would solely require the QA group to regression check on gadgets in that particular media question vary. Examine that to the prospect of deploying the only bundled web site.css file, an method that will usually set off a full regression check.

The uptake of mobile-first CSS was a very essential milestone in internet growth; it has helped front-end builders give attention to cell internet purposes, quite than creating websites on desktop after which trying to retrofit them to work on different gadgets.

I don’t suppose anybody needs to return to that growth mannequin once more, but it surely’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 machine—any machine—over others. Because of this, specializing in the CSS in its personal proper, all the time conscious 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. 

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


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