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 standard 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 is predicated on the precept of overwriting model declarations: you start your CSS with default model 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 initiatives, mobile-first CSS might but be the most effective instrument for the job, however first you should consider simply how applicable 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 am going about tackling the elements you should look ahead to, and I’ll focus on some alternate options if mobile-first doesn’t appear to fit your challenge.

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 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 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 consumer journeys, and infrequently accounts for a larger proportion of consumer visits (relying on the challenge). 

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 occupied with cell from the beginning prevents us from getting caught in a while; nobody desires to spend their time retrofitting a desktop-centric website to work on cell gadgets!

Disadvantages of mobile-first#section3

Setting model 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 have been reverted to their browser default worth in a category identify declaration now have the next specificity. This generally is a headache on giant initiatives whenever you need to hold the CSS selectors so simple as attainable.

Requires extra regression testing. Modifications to the CSS at a decrease view (like including a brand new model) 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 information in precedence order.

The issue of property worth overrides#section4

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

With this in thoughts, I’m creating CSS with a give attention to the default values way more today. Since there’s no particular order, and no chains of particular values to maintain observe of, this frees me to develop breakpoints concurrently. I focus on 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 possibly can have a look at every breakpoint as a clear slate. If a part’s structure seems prefer it needs to be primarily based on Flexbox in any respect breakpoints, it’s high quality and could be coded within the default model sheet. But when it seems like Grid could be a lot better for big screens and Flexbox for cell, these can each be carried out solely 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 will 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 part 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 strategy isn’t going to go well with everybody, I encourage you to present it a attempt. 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. If you’re comfy with specializing in the cell view, have understanding of the necessities for different breakpoints, and like to work on one gadget at a time, then by all means stick to the traditional growth order. The essential factor is to determine frequent kinds and exceptions so you possibly can put them within the related stylesheet—a type of guide tree-shaking course of! Personally, I discover this a bit simpler when engaged on a part throughout breakpoints, however that’s certainly not a requirement.

Closed media question ranges in follow #section5

In traditional mobile-first CSS we overwrite the kinds, however we will keep away from this through the use of 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 beneath 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 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 in a while, time and again. 

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 more likely to introduce undesirable alterations, and our regression testing solely must give attention to 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 may 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 wish with mobile-first), we will wrap the cell 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 model, as we would like the browser default worth.

Bundling versus separating the CSS#section6

Again within the day, protecting 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 once. This enables us to separate the CSS into a number of information by media question. The clear advantage of that is the browser can now request the CSS it at present wants with the next 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 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., 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 remains to be utilizing HTTP/1…WHY?!! What are you ready for? There may be glorious consumer help for HTTP/2.

Separating the CSS into particular person information is a worthwhile job. Linking the separate CSS information utilizing the related media attribute permits the browser to determine which information are wanted instantly (as a result of they’re render-blocking) and which could be deferred. Based mostly 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 at present wanted to render the web page. The remaining CSS information (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 should obtain the CSS file and parse it earlier than rendering can begin.

Whereas, as famous, with the CSS separated into completely different information linked and marked up with the related media attribute, the browser can prioritize the information it at present 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 are able to’t assume that desktop customers at all times have a quick connection. For example, in lots of rural areas, web connection speeds are nonetheless gradual. 

The media queries and variety of separate CSS information will range from challenge to challenge primarily based on challenge necessities, however may look much like the instance beneath.

Bundled CSS

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

This single file incorporates 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="cell.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 present wants. Out of the 5 information 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 challenge’s deployment technique, a change to 1 file (cell.css, for instance) would solely require the QA workforce to regression check on gadgets in that particular media question vary. Evaluate that to the prospect of deploying the only bundled website.css file, an strategy that might 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 give attention to cell internet purposes, moderately than creating websites on desktop after which trying to retrofit them to work on different gadgets.

I don’t assume anybody desires 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 gadget—any gadget—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 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 be a bit extra simplified and productive. 

Generally, simplifying CSS rule creation each time we will is finally a cleaner strategy than going round in circles of overrides. However whichever methodology you select, it must go well with the challenge. Cell-first might—or might not—grow to be your best option for what’s concerned, however first you should solidly perceive the trade-offs you’re entering into.

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