Ticket sales are open! perfnow.nl/tickets.html

Is there a closely-guarded secret to using <dialog> in Safari? Or is it just not working?

❓ A question for web developers ❓ If you do layout in CSS, what's missing? I'm especially interested in hearing about use cases that aren't yet solved by existing CSS layout features. #css #webdev

Why is a strikethrough called a line-through in CSS? It's been like that since at least 1998, but I forget every time I need it.

Working on my talk for @cssday.nl and I just realized it's less than a month away. Not panic time yet, but it's coming fast 😅 Also, early bird pricing ends today, so if you don't have your ticket yet, now's the time! cssday.nl

RE: https://front-end.social/@html5test/116567074336744419 Only at CSS Day! https://cssday.nl

Only at CSS Day! cssday.nl

It is spelled Custom Properties but pronounced CSS variables. It’s British like Leicestershire. Don’t think about it. Similarly Custom Elements are pronounced “web components”

Reminder: On 14th of May CSS Day ticket prices will go up by €75 + VAT. Want to come to cssday.nl ? Ordering now is cheaper than ordering later. See you in June,

We just sent out a TEST MAIL to our mailing list. Last year quite a few people didn't see the announcement mail and missed the early bird ticket sale. So this year we run a test first. If you're subscribed to our mailing list, please make sure you got the test mail. Or perfnow.nl/subscribe

I’ll just leave this here for now. viewportconf.org #web #conference

I forgot I created an entire media query test suite. Wouldn't be too hard to expand it with a container query test suite. https://www.quirksmode.org/css/mediaqueries/mobile.html

Is the email system breaking down? Just now I went to an art gallery and a board game shop, and both proprietors complained that their mails never arrive any more. Coming home, I discovered a mail I was expecting for days in my spam box, while there was no reason for doing so. [1/2]

The second part of my column-filled grid idea: why the original idea doesn't work very well but is nonetheless the least bad option right now. https://www.quirksmode.org/quirksblog/2026/0507-cfg2.html

So I was supposed to answer some Very Important Emails, go shopping, and do a bunch of stupid admin stuff around the conferences ... ... but instead I'm coding a silly effect for the performance.now() home page. Technically counts as conference work, but ...

New blog post: https://quirksmode.org/quirksblog/2026/0505-cfg1.html

Oh look, the #cssday speakers are starting to cooperate to bring DOOM to our audience. front-end.social/@bramus/1165...

Well, I've got a version of my grid article, the one I asked so many questions for lately. It'll likely be a two-parter, with an extra posting about the inner workings of grid.

Reminder: TODAY is the last day you can buy tickets by invoice. From tomorrow on only Stripe payments are possible. cssday.nl/tickets.html

What I want to achieve is this. I have in fact achieved it. But it requires me to explain - the grid filling algorithm - debugging via counters [1/3]

I just realised there's an easier way of doing the little grid technique I've been working on for the past 24 hours. Back to the drawing board.

The following works in Chrome and Safari, but not in Firefox. maxColumns is always 0. Why? --containerWidth: calc(100cqw - var(--padding) * 2); --maxColumns: round(down,calc(var(--containerWidth) / var(--size)));

Has there been discussion about a variant of sibling-index() and -count() that doesn't count hidden elements (display: none)? Might conceivably be useful.

I wrote something about it here: css-tip.com/if-trick/ and yes it should work demo: codepen.io/t_afif/pen/V...

You can do the comparison with math and then use if to check if the flag is 1 codepen.io/propjockey/p...

No, not yet anyway. There is a proposal though. github.com/w3c/csswg-dr...

And is it even possible for CSS if() to compare two numbers? Seems not. color: if(sibling-count() <= var(--comp): red); (--comp is a number)

There is no children-count() similar to sibling-count(), is there?

you can use `counter-reset` with the sibling-index() and then the counter function in the content. ``` div::after { counter-reset: index sibling-index(); content: counter(index); } ``` Here's a demo: codepen.io/editor/amit_...

So it appears that - the content property of ::before doesn't accept integers as a value - it is not possible to convert an integer to a string in CSS Use case: print out values of sibling-index() and a few friends for research purposes.

RE: https://mastodon.social/@perfnow/116454339136969351 Let's welcome the performance.now() conference to Mastodon! #perfnow

RE: https://mastodon.social/@Edent/116442729900708561 Interesting. I didn't know it was ever proposed.

My sister asked me to translate “huppelkuttenhouse” into English. I don’t know. Anyone?

Demystifying block formatting contexts https://quirksmode.org/quirksblog/2026/0416-bfcs.html

It's queryable. OK.

Demystifying block formatting contexts quirksmode.org/quirksblog/2...

OPERATION EPIRUS FURY :-D

Bluesky is down (for me?). Good to have Mastodon to complain on.

"The Web Developer Tools panel has crashed." ??? Never seen that one before. (Firefox)

There is no CSS measurement for "the width of the content once the floats have influenced it", right? Ideally I need that width. p img { max- width: 100%-of-content-after-floats; }

The story of my first browser bug in, I don't know, five, seven years? https://quirksmode.org/quirksblog/2026/0410-bugreport.html

Oh, and Skymoth sends my toots on to Bluesky again. A bunch of them landed late last night, it seems. Let's see if this one arrives within a few minutes.

LLMs are a religion. For gullible people. I mean, the faithful continue to take the LLMs' hallucinations seriously. And even make them the cornerstone of their businesses.

RE: https://front-end.social/@jensimmons/116377939874317650 That's fast ...

My first bug report in many many years Safari :has(:empty) bug. Includes a workaround. I probably got some of the details wrong, but I'm fairly certain of the gist. https://quirksmode.org/browserbugs/safari-has-empty.html

RE: https://mastodon.social/@lloydi/116369154437719653 Oh bloody hell brothercake died. It's been ages since I last saw him, but we were occasionally in touch on the Socials. He'll be missed.

Good Lord, the Safari bug is actually giving way to my brilliance. Or my perseverance. Or my stubbornness. In any case, the quite large lobe in my brain that's dedicated to reverse-engineering browsers is getting its first workout in years, and ... work out fine.

Oh wow, the Google AI overview is so terribly wrong. I asked about the possible causes for the bug, and it blantantly claims that Safari has the following bugs, sourced to bugzilla and applicable to Firefox. BS.

Let's validate a browser bug. Please use SAFARI (Mac or iOS) to go to the page below. Do you see a list of games for sale? (Expectation: no) Resize the page vertically. Do you see a list of games for sale? (Expectation: yes) https://quirksmode.org/spelverkoop/