CSS is DOOMed

Tomorrow I will be the special guest on WeAreDevelopers Live 🎙️ where I will talk about my latest project: DOOM but fully rendered using CSS.

https://www.wearedevelopers.com/en/live

6 days. 6 reasons to come to #btconf Düsseldorf 2026 🧵

1. James White
2. Curiosity
3. Niels Leenheer
4. Code
5. Marjan van Aubel
6. Design

27–28 April → https://beyondtellerrand.com/events/dusseldorf-2026

@btconf is 1 week away. See you there!
If you haven't got your ticket yet do it now!!
https://beyondtellerrand.com/events/dusseldorf-2026/tickets

Most of my talk preparations follow this pattern:

1. Idea
2. Worry about having enough content
3. Worry more about finishing 20 minutes early
4. Make slides
5. Practice
6. Panic, because it is 20 minute over time
7. Remove about a third of my talk
8. Panic, because I removed all the good jokes...

Care about the future of the web?

"The Web You Want" is a free community event in Amsterdam on digital ethics, sustainability & accessibility.

It's happening TOMORROW, Friday, April 17th!

There are still 12 spots left to grab for free:
👉 https://the-web-you-want.org/

I'm doing a new (ish) talk at “The Web You Want” tomorrow! https://the-web-you-want.org

It is about 5 *essential* ingredients of a web that serves us all

If you're in or near Amsterdam, join us!

Tickets are free.

There's excellent speakers like @marleenstikker, Sanne Peters, @html5test and Justus Sturkenboom!

Just 15 places left for The Web You Want, tomorrow.

☞ https://gath.io/GfyzG5Jyet6vw0J5_eyKk

I've been to the first @btconf in 2011 and then to almost all following events in the last 15 years. It's no secret that it is my favourite conference and one of the most important drivers for my creative energy and career.

Conferences are expensive to visit and it's hard to tell how much effect they can have on you before visiting for the first time. But @btconf is 100% worth it and such events are now more important than ever: https://beyondtellerrand.com/events/dusseldorf-2026

HTML DOM in Canvas? No. DOOM-ception in Canvas.

Maybe I should be working on my slides for Friday, instead I'm at @smashingconf.com creating a playable DOOM terminal in my cssDOOM project. It is a Canvas with an iframe of cssDOOM. And... it works. You can play DOOM in DOOM.

WebSerial has landed in Firefox Nightly !! 🎉

Enable it in about:config and it all just works as expected. Took a brand new ESP32 and had a new Bluetooth proxy added to Home Assistant within 2 minutes 👌

First talk of the year is done: CSS is DOOMed, which was just a very last minute idea for the @smashingconf Jam Sessions.

10 minutes. No preparations. No slides. Off the cuff. But I had lots of fun playing cssDOOM and showing how it works under the hood.

Arrived in Amsterdam for @smashingconf and booked an apartment for the coming days.

But… I did not expect to step into a Rembrandt or Vermeer painting… 🤩

Let me tell you who this @html5test guy is and why I am happy to have him on stage at #btconf Düsseldorf. https://beyondtellerrand.com/blog/speaker-intro-niels-leenheer

Is it just me, or has Keynote has become terrible to use lately. Copying text blocks changes the font.... Copy source code... pasting a table?!?!

On a side note, the flame thrower video – and this one with the smoke machine – were one of the funniest things I've ever filmed for a talk. Not part of the final cut, but several times during filming cars drove by, slowing down trying to assess what was happening... 😅

The code for this is open and available at https://github.com/NielsLeenheer/WebDmxController

Want to know more? I have an upcoming talk about this – no promises on a live demo of the flamethrower – at @btconf later this month.

Tickets are still available:
🎟️ https://beyondtellerrand.com/events/dusseldorf-2026

You can also connect MIDI controllers and gamepads which set classes when you push a button. So you can trigger the flamethrower from a button.

Connect a heart rate monitor too. So imagine a CSS animation that controls the speed of the fireballs... timed to your heart beat. Thermal runaway.

CSS Flamethrower 🔥

We definitely need dedicated CSS specification for this. The flamethrower is connected with DMX and WebUSB. All DMX devices including lamps and stage FX devices get a DOM element with an id. You can use CSS to set colours or... throw flames.

Over the last week I've fixed some cssDOOM issues and improved the gameplay to better match the original game. And the best part – because it is just a website, you don't have to download any updates.

Best browser to run this is still latest Firefox, with Safari a good second.

https://cssdoom.wtf/