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Using REM Doesn't Make Your Website Responsive - Here's Why

Caio Marcellus Cabral on August 30, 2023

You can access this article in portuguese here Você pode acessar este artigo em português aqui I love being part of technology communities. Besi...
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moopet profile image
Ben Sinclair

This reminds me of a university project where one of the requirements was a 10-page paper, so I kept upping the font size until it went onto 10 pages. I think when I handed it in it was 46pt.

I did not do well.

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franklivania profile image
Chibuzo Franklin Odigbo

This is very true. For more fluidity, I use em. And yes, you do not need media queries to make responsive sites. I use this a lot and when I show others the little media queries I use for responsiveness, they marvel 😅

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marcelluscaio profile image
Caio Marcellus Cabral • Edited

That's nice! I use em a lot on my paddings

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spo0q profile image
spO0q 🐒🎃

As a backend dev who sometimes pretends to write CSS, I use clamp() and some linear function to keep things responsive.

I try to avoid rem but now I know why ^^. Thanks.

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marcelluscaio profile image
Caio Marcellus Cabral

Oh, clamp() is really useful, and I am going to talk about it on my next article, about fluid typography!

Thank you for reading =D

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spo0q profile image
spO0q 🐒🎃

very nice. I'll read it!

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khair_al_anam profile image
Khair Alanam

Pretty insightful article on REM and responsiveness! I would also like to add that you can make the font-size responsive without using media-queries by using the clamp() function in CSS.

font-size: clamp(minimum_size, increment, maximum_size);

We set a minimum size for the text, and when we increase the screen size, the increment will do that font size increasing and then it will stop increasing when it reaches the maximum size.

It's supported by all the major browsers (except IE) so it's good to use.

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marcelluscaio profile image
Caio Marcellus Cabral

Excelent, Khair! I am actually going to talk about clamp() on the next article about fluid typography =D

Thank you for reading

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khair_al_anam profile image
Khair Alanam

You're welcome =D

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d7460n profile image
D7460N

Thank you for this article! Very informative.

CSS and typography are like two dancers along the Beautiful Blue Danube.

If I may, what are your thoughts on native intrinsic typography? Native, as in without dependencies.

Possible?

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marcelluscaio profile image
Caio Marcellus Cabral

Really happy you liked it!

About intrinsic typography, thank you for bringing it up! I hadn't read anything about it.

I'll delve into it

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techsnack profile image
TechSnack - Technology Tutorials

Great article. I work with responsiveness and accessibility mostly every day and I still learned something from this! Excellent work.

Also, are we going to dig into clamp next?

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marcelluscaio profile image
Caio Marcellus Cabral

Hey, TechSnack, I am really happy to read your comment!

Yeah, we are going to cover clamp and vw units on the next article on Fluid Typography. Hope you like the next one too =)

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techsnack profile image
TechSnack - Technology Tutorials

I bet I will enjoy it. I learned some of the deeper reasons behind why certain things are implicitly done the way the are.

I always enjoy having a deeper understanding of the why's and the how's rather than just the how.

Keep up the great work!

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drubb profile image
drubb • Edited

There are of course still use cases for absolute measurements like px.
Imagine a text paragraph on a small screen, with some horizontal padding. It would not make much sense to increase the padding with the font size, this would waste precious space. So in this case I'd still prefer px values for the padding.

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marcelluscaio profile image
Caio Marcellus Cabral

Oh, yes, drubb. I am mainly talking about font-sizes here. Of course in some properties you could use px, like border and box-shadow (even thoug you could use other units too).

For paddings I normally use em, and in some edge cases I could sprinkle some px, even though I propably would go for vw in that case you mentioned.

Thank you for reading and for the discussion =)

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artydev profile image
artydev

Very informative, thank you very much

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marcelluscaio profile image
Caio Marcellus Cabral

Thank you for reading =)

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devdufutur profile image
Rudy Nappée

That's what happens when we use PX for font sizes: we ignore user preferences and impose the exact size we've chosen.

🤔🧐

Actually all modern browsers handle adapting font size in px according to user preferences...

px css unit doesn't actually rely on screen pixels but reference pixels, equivalent to 1/96 inches, meaning dependent to the density of screen in dpi but also the zoom level of the browser.

I don't really see a good reason using rem instead of px excepts increasing difficulty of code.

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stefanjudis profile image
Stefan Judis

Actually all modern browsers handle adapting font size in px according to user preferences...

I don't think that's true. I just tested Chrome and Firefox and neither adapt rendered font size defined in px to font default settings. Appearance -> Font size: very large (Chrome) or General -> Fonts -> Font size (Firefox) don't affect font sizes when they are defined in Pixels. Percentages or rem on the other hand do respect the default font size.

Image description

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devdufutur profile image
Rudy Nappée • Edited

Indeed my mistake. As mentionned in my reply to @marcelluscaio I was refering to zoom level, I didn't knew this font size setting.

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marcelluscaio profile image
Caio Marcellus Cabral

Great demo, Stefan! Interesting to notice that in font-sizes the percentage unit refers to the default font-size, so 100% is equivalent to 1rem

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marcelluscaio profile image
Caio Marcellus Cabral

Sorry, but that is not the case.

They do scale font with zoom, but if you set your font to pixels they are not going to adapt it to the user's font preferences.

So, you should not set your font size in pixels.

And I know it takes a while to adapt to writing in REM, but you eventually get used to it =)

And yeah, pixel actual size varies from device to device, due to screen density.

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devdufutur profile image
Rudy Nappée

What difference do you make between browser zoom and user preference ? Can you provide an example ? Thanks

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marcelluscaio profile image
Caio Marcellus Cabral

Changing the default size is like this: chromestory.com/2022/09/change-tex...

On the other hand, when you zoom in, browser adapts content, unless it is related to viewport size.

Again, using REM is not outdated in any way.

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devdufutur profile image
Rudy Nappée

Thanks for the precision, didn't knew this feature.

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artxe2 profile image
Yeom suyun

Using em as the default unit to create
responsive websites is incredibly convenient.
However, it does not respond to system fonts.

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marcelluscaio profile image
Caio Marcellus Cabral

It can help indeed, Yeom. I just wouldn't recomend using em for font sizes because a change to the HTML structure could ruin your typography system.

I love using em for paddings, for example, since it is always pointing to the same element.

Thank you for reading!

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wakywayne profile image
wakywayne

Very interesting, I had no idea that px were absolute like that!

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marcelluscaio profile image
Caio Marcellus Cabral

I'm happy it helped =)

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khairunnisaas profile image
Khairunnisaas

ahh... learn something new everyday, thanks for sharing this!

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marcelluscaio profile image
Caio Marcellus Cabral

Thank you for reading =)

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malikbenkirane profile image
Malik Benkirane

for 1sec I thought this was about sleep and circadian patterns in human biology
maybe next time 😇

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marcelluscaio profile image
Caio Marcellus Cabral

Having a good night's sleep certainly helps with everything - including building better websites, Malik! xD

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samy profile image
Samuel Urah Yahaya

Nice and Informative!!! Picked up a few concepts from this.

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marcelluscaio profile image
Caio Marcellus Cabral

I'm happy to read that =)

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giuliano1993 profile image
Giuliano1993

This is a great article, probably the best explanation about how and why use rem i've ever read! I really appreciate that ( and also the rest of the article of course ) I will for sure apply what i read in my projects to come, thanks for this great work! 😁

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marcelluscaio profile image
Caio Marcellus Cabral

This comment fills me with joy =D

Thanks for reading and leaving a comment

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giuliano1993 profile image
Giuliano1993

Thank you for writing it! 😁
Really, I saved it to share to anyone needs a good explanatin about the topic 🙏
Hope to read more like this 😃

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davidecarpini profile image
Davide Carpini

Amazing article, you saved me lots of hours! I will save it between my favorites! thank you!

what are your thoughts on changing the root: element font size based on media query/clamp,
instead of changing each heading/text font size based on media query/clamp?
isn't it enough to change the root font size to make it responsive?

cheers!

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Dmitriy Yoo

Amazing article! Thank you! 😄👍