Two and a Half Weeks: Four Talks

Disclaimer: It has been exactly 20 days but it felt like two weeks and a half. And it sounds better.

I did it again. Actually after having done a conference marathon last year with my talk about our large scale CSS refactoring project aka Project Ironman I thought I’ll never do something like this again. Either it might not happen again or I might decide to don’t do such an exhausting (but great) thing again.

After I did a small break after ScotlandCSS in June last year I did another presentation at a local Google Developer Devfest in Düsseldorf last year. I put the refactoring into its bigger context (roll-out of a Design System) and called the talk “Rebuilding an aircraft on the fly“. The feedback was overwhelming and actually I’m so passionated about Design Systems and like to be involved and contribute to its community and if it just sharing some experiences we’ve made I thought to do something with this on maybe one or two conferences in 2017.

It basically started in Sofia end of March. I had been invited to speak at MobCon Europe. I’ve prepared a 135 slides slidedeck about our journey with rebuilding our UI at large scale and rolling out a Design System. The feedback of my session was overwhelming as the survey after my talk revealed:

Learning Value: 4.42
Session Content: 4.68
Speaker’s Pace & Timing: 4.58
Speaker’s slides: 4.89
Speaker’sProfessionalism: 4.79
Audience Engagement: 3.89
Speaker’s Knowledge: 4.95
Average Result: 4.6

The rating scale was from 1 – 5 and this are the results of 19 votes. Given that around 200 people attended my talk this is the evaluation of 10% of the audience.

I wouldn’t apply / submit for a talk if I wouldn’t be sure that the content is good but I didn’t expect people perceive it as that good.

So it came that I had a tough schedule ahead I felt confident to commit to after my experiences with the new talk topic.

12nd May – WeAreDevelopers, Vienna
23rd May – Code Europe, Wroclaw
25th May – Code Europe, Warsaw
1st June – Shift Conference, Split


Oh. I got sick the weekend before and two days before the event I even had to call in sick at work. Some medicine and hours of sleep later I made it to the Airport on the 10th of May.
I was nervous already the weeks before. People might think it gets easier and if you’ve already spoken at more than 10 conferences than it becomes like a routine to do a talk. That’s not how it is for me. You do more talks, you gain more experience, you want to get better, you have higher expectations in yourself, the audience might have heard of you, they might have a higher expectation as well, people paid for your talk etc. All this came to my mind after having done my first talks.
Back to Vienna. I had a good flight, took the City Airport Train and bought a 72h Vienna ticket for public transportation.
I arrived at Ruby Marie Hotel. I  have been at a lot of fantastic hotels before, especially because trivago offers from time to time a very luxury company trip but this Hotel was so lovely and I loved every detail. Have a look at the picture which I took at the rooftop before leaving Vienna on Saturday the 13th.

I was super tired but wanted to get to Schloss Schönnbrunn on the day of my arrival. When I’m at locations for public speaking engagements I normally do “sightseeing speed dating” with a very tough schedule. Schloss Schönnbrunn was on my schedule this time. I ruined a super market next to the Hotel with picking up a beer and accidentally throwing a couple of cans of the floor. Some exploded. What a mess.  But Schloss Schönnbrunn was worth the visit.

One reason why I was nervous this time was the amount of people at the conference. At the end it have been ~3800. The queue was bit long and people had to wait. 4 coffee machines for all of them. Developers tend to get sad if they don’t get coffee. The venue was super cool. The Marx Halle in Wien. The main stage was incredibly huge with space for around ~1600 people. Impressive in size. The biggest event I have ever been to.

I’ve spent the first day with a lot of networking, doing some finetuning of my slidedeck and listening to talks. My personal highlight was the talk of John Romero about the early days of ID Software and every time he asked, who had played this game I could raise my hand. I played them all. In god mode because I was 12 and afraid of all those monsters.
At the end of the first day there was a speaker party which I attended for a couple of hours before leaving around midnight to the hotel.

The day of the talk. I’m always in a tunnel already at breakfast. My talk was scheduled at 10.30am. A perfect time for me. I went to Harry’s talk to get a bit distraction before my talk and went over to my stage at 10.15am.

The room offered seats for around 330 people, but more than additional 50 to 100 hundred were standing around. The challenge of that talk was that I basically somehow squeezed the 45 minutes talk from Sofia into a 30 minutes talk. I had 119 slides instead of 135. I had to go through the story very fast but I followed the thread and at the end I’ve exceeded my talk time with 1 minute which was also ok because there was a break after my talk. Otherwise exceeding your talk limit might be unfair to the following speaker.

Questions came up, and people came to me in person and we discussed in a small round about Design Systems. Others provided me with nice and valuable feedback while I did a small walk through the venue after my talk. One of the nicest feedback you can get is when people tell you your talk motivated and inspired them.

I went to the hotel in the late afternoon to get an hour of rest and enjoyed another speed sightseeing tour in the evening.

Thank you Vienna. Thank you WeAreDevelopers.

Slides of my talk:
The recording of my talk:

Code Europe Wroclaw & Warsaw

I’ve changed my talk from Vienna a bit. The session length for Code Europe was again 45 minutes and I put a bit more focus on the early history of UI development at trivago. All in all the story has been the same but with a bit of different content and focus. I actually have never done the same talk twice.

Hello Wroclaw. There’s only one high building.

What a tiny cute Airport. When I entered the entrance hall there was a Code Europe booth and people I’ve never met before where smiling and waving at me. What a nice welcome. The first time in the next days where I thought: Wow this is greatly organized with a lot of love to the details. And kept thinking this during my whole stay in Poland organized by CodeEurope. I shook hands with the people and have been told that the driver which gets me to the Hotel will arrive in 5 minutes. So he did. And I’ve met Ian Philpot. We were brought with a 20 minute ride to the Hotel. We couldn’t check in because it was 1:15pm and the rooms are not available before 3pm. So Beers.

I entered my room at 4.30pm. I did a 1 hour nap and made myself ready for the welcome drinks session in the hotel at 6pm. I’ve received a message from the organizers that I can pick up a package at the reception.

Wow. Thank you!

I went to the welcome drink session, took accidentally the strongest craft beer available and realized I was already tipsy.

The conference day Wroclaw. Did I mention the organisation? There was a shuttle plan and one bus and a taxi were driving between Hotel and venue nearly every hour. I took the first bus although my talk was at 12.45, but I’m  not going just to speak myself I also want to contribute to the conference as an attendee. The venue was lovely, a lot of stages, I think it have been 6 or 7. I explored mine and I liked it.

I visited a few talks and went to the VIP room around 10pm. Such a lovely venue. But now preparation time for my talk. I was more nervous than I needed to be but on the other hand I wanted to deliver a decent talk. Coffee, charging laptop, toilet, coffee, toilet, toilet. That’s how the last hour before my talk looked liked.

I went on stage on did my talk. It went very good, I was confident and on 100%. The room was overcrowded like at WeAreDevs, I guess it could have been around 400 people. But then something happened. After around 75-80% of my talk the microphone didn’t work anymore. I realized it but continued because also nobody from the technicians seem to be at their desk. But after a few seconds I stopped and people from the audience mentioned they couldn’t hear me. Oh. F***. What to do now? I looked to my left where the table of the technician was but apparently he wasn’t there. I was once again reminded from the audience that my microphone still didn’t work. So then let’s see how can I fix it, so I went off the stage to the area of the technician. When I arrived 20 meters later at his desk, he suddenly jump up on his chair. Apparently he had taken a nap during my talk. I was highly irritated but apparently he as well. He handed me another microphone and apologized. Some people were laughing about this situation. “So what?” I thought and went back to stage, a bit out of the flow I went a couple of slides back and finished the talk.

I answered again some questions in person and did a small video interview for a local tv station.

I spent the day with listening to other talks and networking with other attendees and speakers. In the evening we had a speaker dinner in the old town of Wroclaw. Nice food, nice chats and a lovely location.

We were brought back to the Hotel at 11.30pm and at the next morning we had a transfer by bus to Warsaw. The Wifi within the bus didn’t work. But also most people including myself spent the time with some chats, reading a book, watching a moving or doing a nap.

During that time somebody dropped that tweet to me.

Thank you very much Luke! Love that shot.

I was very much looking forward to Warsaw and I have not been disappointed when we arrived in Polands capital. Impressive, especially the Palace and all the modern Skyscrapers around. Check-in at the Hotel. I had planned to go a free sightseeing tour which should start at the Palace with another speaker. From the window it looked like it is only a 10 minutes walk.

I went to my room and did an interview call for a german magazine and there was a CSS-in-JS discussion in the trivago tech slack channels, where I thought I should leave my two cents in. At 3.45pm I realized I have to leave when I want to attend the tour, so I did. But the Palace was 20 minutes away through a labyrinth of tunnels under the streets. And when I arrived at the Palace I realized the starting point was somewhere else, Google said I had to walk 2.1km. WTF. No. And the Internet connection broke. I walked around a bit at the palace and then it started raining and then I’ve ended up in the office of a big global tech company. Networking and having a coffee.

In the evening I attended another Welcome drink session and spent the evening at the bar of the Hotel. I was sober but I did not really sleep well. The location in Warsaw was the stadium. Yes the one that had been build for the UEFA European Championship 2012.

I arrived a bit later as planned at around 11am at the venue and the organizers were so nice to give a bit of a tour through the inner stadium.

My talk was scheduled at 17.25, the last slot. And my energy went down every minute of the day, I felt like my batteries are completely drained. Back to the speaker lounge, coffee and coffee, a walk in the fresh air, more coffee. My Garmin Vivoactive HR realized with its optical heart rate sensor that I shouldn’t drink any coffee anymore.

It ended up in one the most hardest talks I’ve ever done, despite the one I’ve done after nearly not sleeping at all last year in Amsterdam but somehow I made it. This are maybe the situations where you get better in with a bit of experience. I made my performance, there were only very few free seats left in the room. And I’ve had some nice chats again after my talk.

Another speaker dinner at the evening and my alarm clock was set to 4.30am. I took the first shuttle to the airport at 5am, slept there for 1h again and took my plane at 8.30am.

I arrived at home around noon somehow made it through the afternoon and fall asleep in the evening. I slept 16h.

Slides of my talk:

Shift Conference

5 days after my talk in Warsaw I found myself in a plane again. This time to Shift Conference, a single track conference in Split. Apparently with Croatia Airlines everybody gets a snack and two drinks. Have a look Air Berlin, Eurowings and Co.

Oh and what a beautiful view while landing:

Boris – my driver – picked me up at Split Airport and brought me to my Hotel. It was already late, 8pm. So I bought some food on the street next to the Hotel and went to bed early. After removing my contact lenses I found out that I apparently forgot my glasses. I searched for them without seeing much in my luggage but couldn’t find them.

I had a good night and after breakfast I walked to the venue which was around 1km from the Hotel. In. A. Theatre.

I registered and had a look at the very majestic venue and its stage. Oh. My. God.

My talk was scheduled at 15.15pm. So I’ve watched a couple of talks. Most impressive was to see how Chris Heilmann did his talk although only in the beginning the slides were shown, basically he had to do his talk without that the audience could see his slides. What a speaker machine.
I also hoped to not run into technical issues this time, after the microphone situation at Code Europe and in April when I did a live demo at Symfony Live I had to interrupt my talk for about 5-7 minutes until the beamer had been fixed.

30 minutes before my talk I went backstage. There was a small break before my talk. Here’s a picture I took after I’ve set up my macbook.

Here’s another picture after I had been introduced and walked to the speaker desk while my intro song was played. I had chosen “Let there be rock” by Tocotronic. Actually I was super excited but because lots of lights were spot on me it was somehow hard to see something, that’s why I look a bit serious. This was such a amazing moment going on that stage.

My talk was perceived well. I also had the feeling it went well, I have only seen 50% of the recording yet but I’m satisfied so far. I’m reading still too much speaker notes but it helps me to follow the thread and do my talk in time. But something I want to improve if I’m speaking again. But also I think its particular difficult if you adjust your talk for every conference.
I had some really long chats with some attendees after my talk. We planned to stay in touch.

The speaker dinner on the first day was Diocletian Place in the old town of Split. What a venue for a speaker dinner. I found a horse there.

But this was only the beginning. There was a official party at a club in the middle of Split, the Central the Club.

I don’t go too often into clubs anymore but after this amazing day it was no question whether to go or not. Again I got some nice feedback from attendees about my talk and had several other nice chats. What a great location to end the day of a speaking engagement.

Day 2 of Split Conference. I was especially looking forward to the talk of Una Kravets and Laura Carvajal. And I was not disappointed after their talks. It was more the opposite. My expectations have been exceeded. Especially Laura’s talk was very informative for me because accessibility is a topic which I’m very passionated about too and it was so interesting to get some insights and learnings from the Financial Times.

As I was not really hungry I’ve used the lunchtime of around 90 minutes to walk around Split and Split Port.

There was another speaker dinner at the Gallery of Fine Arts which offered the opportunity for another couple of nice chats with other speakers.

I left not too late because I had to get up at 4.20am because Boris was picking up Laura and me at 5am so that we could get our planes. Boris was very reliable. The driver you wish for.

Heading back home. And the Alps. I love the Alps.

It has been a great time. I’m grateful to have been part of the conferences and happy that everything went well.

Slides of my talk:
The recording of my talk:

Conference Recordings

And here we go. Most of the recordings of my conference talks in 2016 related to Project Ironman / Pattern Library at trivago have been published. I’m looking forward to the last one to be released hopefully soon. It is the recording from ScotlandCSS which is not online yet.

Let’s start with my first conference talk in english ever. OMG. You need to read my The Junior Speaker article to understand what happened here. Nevertheless although I’ve been stuck in a “Umm…. bascically”-mode at the end people really liked it and the feedback helped me a lot to understand where I need to improve the talk and myself.

The next one in chronological order of the conference tour is my talk at the Symfony Live 2016 conference in Cologne. What an incredible amazing audience. They’ve appreciated and got all my (stupid) jokes. Thanks to my colleague Jan van Thoor for assisting during this talk. I love it. No speaker notes were needed for this talk in my native language. A bit sad that the quality of sound and video is so bad.

Codemotion Amsterdam. The most exhausting talk on my conference tour. I had such a bad night but my performance is way better than in my remembrance. Unbelievable what I was able to do after 90 minutes of sleep in a hostel and 2 liter of coffee before the talk.

In case you watched them all (I hope you didn’t) you might have seen an improvement in performance. I do at least. At Frontend United I sticked completely to my speaker notes and I didn’t walk miles on the stage. Might be related to the fact that I needed my speaker notes.

Looking forward to the recording of my talk at ScotlandCSS. Although I did 7 talks in 6 weeks and had only a few hours of retrospective after some talks I tried to improve with every single one. And the ScotlandCSS was the best one. At least in my remembrance.

The last 4 weeks

A lot of things happened in the last weeks.

The lovely team from ScotlandCSS did a very nice Interview with me and published it 4 weeks ago.

Nearly the same time I published an article about our experiences at trivago with integrating a pattern library at large scale. I shared my experiences with Brad Frost who retweeted my article on twitter. Once again I realized how important it can be to share your experiences and contributing to the community with sharing your knowledge. I have received a lot of very valuable feedback after I wrote this article.

We are very happy about our progress with integrating a pattern library, establishing a Design System and – with this – rebuilding our UI at large scale at trivago.

Not only in web, in general we are finally at the point where Design Thinking became part of our daily business. Read how our Apps Team redesigned the android app upon a Design System.

But I am myself concentrating on the technical part of integrating the Design System / Pattern Library code wise. Also related to the fact that I am a very untalented Designer.

And I am busy with doing talks and preparing for my next talks at Codemotion Amsterdam, Frontend United and Scotland CSS.

A good chance to practice your talk is a nice and lovely Meetup like the Webworker NRW in Düsseldorf. They invited me for practicing my refined version of my talk “Large Scale CSS Refactoring at trivago”.

I did so. And enjoyed it very much.

You can find the slides to my talk at Webwork NRW here.

After that I started to prepare my talk “Pattern Library meets Symfony” for the Symfony Live Cologne 2016. With this talk I wanted to cover more the integration part and the reason for creating the Pattern Library. Basically a talk version of the article above.

But the JSUnconf came in between. As trivago was gold sponsor I went there with my lovely colleagues to help with our booth. Although I didn’t sleep well I decided to propose my talk which I had already in beforehand contributed at the website. I was a bit surprised that so many people showed interested in the topic large scale CSS refactoring and so I received a lot of hearts during the voting session.


And so it happened that I did my talk shortly after the voting (my first talk at a (un)conference in english). It went quite well, although I think there is still plenty room for improvement.

I have received a lot of valuable feedback again and hints for making the talk even better. Also I was very happy about the Sketchnotes @filtercake did of my talk.


I was even asked to do a Q&A / Workshop session the day after to give some more insights and answer some questions. Around 10 people attended it and it was a nice chat about the talk and helped me also to understand where I can improve it. I shared the slides of this talk on speakerdeck. Furthermore my talk was recorded and I am looking forward to the see the final cut.

Next to doing conference talks on the weekend I obviously still had to do my work at trivago. Which I enjoy every day. We did the acceptance of the first business critical element redesign based on the pattern library. And by the way it was our most business critical element. My lovely colleague @DejanUlcej published a great article which covers the challenges behind the redesign from design and UX side.

And then it was already April, the 29th. Symfony Live 2016 in Cologne. Knowing that I was the only Front-End speaker at this conference I took the chance to entertain the people and presented them in a funny and charming way why we introduced a pattern library at trivago and how we currently trying to adapt this to our core product the trivago hotel search which uses Symfony on the backend side.

I did this talk in german and realized it is a bit easier to entertain people in your native language 😉 Same as the JSUnconf talk it was recorded and I can’t wait to see it online soon. I put the slides already on Speakerdeck.

All in all it is completely different to talk to a audience full of back-end developers (I like them) and also it was cool to have some alternation in the Large Scale CSS Refactoring talk marathon.

Now I am really looking forward to do the final refinement of my talk and prepare variations of it for Codemotion Amsterdam, Frontend United and Scotland CSS.

I also once again realized how much work it is to prepare and present a talk. Often I have the feeling people think it is fun and you just open your laptop, pick a already existing presentation and talk about it. No this not how it works for me. The more I appreciate if people thank me for what I am doing in my free time and a big thanks to the organizers of Sensiolabs who even welcomed me with a nice little present.


It is the small things that counts…



Browser support & fallbacks for CSS

Not all browser provide the same capabilities e.g. in support of some (newer) CSS features. In case we want to use a CSS feature with limited support, it is our responsibility as developers to provide a good fallback so that users with a browser that supports the feature can actually enjoy it, while the users which browser doesn’t support a feature will still be able to access our content in a similar way.

The most excellent site i am aware of is which provides you detailed information about browser support of a feature. Sometimes you might find that a certain feature is supported, but slightly different across browsers. For example it might need a vendor prefix, or slightly different syntax. You can almost use different syntaxes alongside and let the cascade take care of which one wins. For this reason, always place the standard version last. For example to apply box-sizing as a border-box value you might need to introduce a vendor prefix to support e.g. Android 2.3 devices.

.box {
-webkit-box-shadow: 0px 1px 4px rgba(0,0,0,0.2);
box-shadow: 0px 1px 4px rgba(0,0,0,0.2);

Every browser supporting the unprefixed version will use box-shadow while the android 2.3 stock browser will use the prefixed version because it has no implementation of the unprefixed version.

Most of the time it’s a good practice to provide fallbacks, so that your site doesn’t break in older browsers, even if it doesn’t look as fancy in them (Do websites need to look the same in very browser?)

Lets take as an example a linear background. If you know how the cascade works implementing a fallback is very easy (due to the fact that CSS is so fault tolerant and everything is just ignored what a browser does not understand).

If you want to use a linear gradient from yellow to red, you might to apply the average of the two gradient colors first before defining the linear-gradient. So in case the browser does not support it, it will stick to the rgb() value otherwise it will apply one of the following declarations:

.selector {
background: rgb(255,128,0);
background: -moz-linear-gradient(0deg, yellow, red);
background: -webkit-linear-gradient(0deg, yellow, red);
background: linear-gradient(90deg, yellow, red);

However, sometimes it is not possible to provide decent fallbacks through the cascade. As a last resort you could use tools like modernizr, which adds classes like csstransforms or no-csstransforms to the root element, so you can use them to target elements only when certain features are supported, like e.g.:

.my-headline {
color: #333;
.textshadow .my-headline {
color: transparent;
text-shadow: 0 0 2px #333;

if the feature you are trying to create a fallback for is sufficiently new, you could also use the @supports rule, which is the native modernizr. For example the CSS grid specification might me a good use case for this.

.my-element:before {
content: "does not support css grid";
@supports (display: grid) {
.my-element:before {
content: "supports css grid";

However, for now be wary of using @supports. By using it we limit our effort not only to browser that support the CSS grid, but also to browser that support the @supports rule. Maybe a more limited set.

Last but not least there is always the choice of using a few lines of home-baked Javascript to perform feature detection in the same fashion as a feature detection library. The main way to determine whether a property is supported is to check its existence on the object of any element. An incomplete example for flexbox support might look like this:

var docRoot = document.documentElement; //html-node
if ('flexBasis' in {
else {

If we want to test for a value, we need to assign it to the property and check if the browser retains it. Because we are modifying styles here and not just testing for their existence, it makes sense to use a dummy element:

var docRoot = document.documentElement;
var dummy = document.createElement('p'); = 'linear-gradient(blue,yellow)';
if ( {
else {

Of course if you want to test for multiple features both should be converted to a function.
Testing selectors and @rules is a more complicated, but follows the same principle: when it comes to CSS, browser drop anything they don’t understand, so we are able to check if a feature is recognized by applying it and checking if it was retained.

Keep in mind that even if a browser is able to parse a CSS feature this does not mean that the feature is correctly implemented, or even implemented at all.

Project Ironman – Large Scale Refactoring @trivago

I had the pleasure to give a presentation about Project Ironman at a user group in Dortmund.

Project Ironman was the technical migration of the trivago hotel search’s existing CSS core to a pattern library based user interface.

After a long journey, we started to establish a Design / Frontend System from the beginning of 2015 at trivago incl. introducing a pattern library, a atomic design workflow, new coding guidelines and adapted several methodologies like BEM or ITCSS to help us maintaining and developing our CSS/UI at large scale.
Some of the top-level goals of creating a Design System was to ensure consistency in code and design of all our applications as well as reducing technical debt and keeping our application scalable.
I gave a lightning talk at the beginning of 2015 to present our learnings and the issues caused by not having a complete design system at the LeanUX Meetup in Düsseldorf.
In less than a year we were able to develop the base of a new Frontend / Design System and started to redesign / reimplement some of our applications like our trivago company pages.

Nevertheless implementing a new CSS / frontend foundation in our core product the trivago hotel search was a completely different challenge. Around 100 people including Developers, Product Owners and Designers work on this application and a lot more have a stake in it, so there is now way around to do smooth (agile) transition and keep (product) development freezes, which will normally be caused by a refactoring, as low as possible.

So therefore we decided to migrate the CSS foundation to the new base we have developed in our Design System in a very short timeframe and we only had to postpone a few UI related features. After this step is done we are able to built new UI components on a solid, modern and sustainable base.

The project was a huge success, the proposed timeframe was 4 weeks and with an amazing spirit due to our incredible engineering culture and people we were able to finish this project within 3 weeks including positive metrics on the business side.

We are currently working on a blog article about this project and we will publish it on our trivago tech blog as soon as it is finished.

Until then, you might have a look at the slides.

The talk was presented at the OpenTechSchool Meetup Dortmund and gives insights and background about the project scope, its implementation and the business value.