Chrome Dev Summit 2014

Chrome Dev Summit 2014 website screenshot

Built in-house by our own Paul Lewis, the CDS website showed how to build a great mobile web experience for conference visitors.

Behind the scenes

Remarkable is the smoothness at which the site runs in various mobile browsers. It's utilizing the layout and paint cycles of the browser in the best way possible.

New web platform features used

  • Service Worker
  • Manifest
  • Theme Color


  • Expending cards
  • Responsive grid
  • Material Design

Source Code

The Interview


When Paul set out to built the site, a key priority was to embrace Progressive Enhancement. Instead of designing for desktop, he built it for small screens first, then build up to larger screens – progressively enhancing, instead of gracefully degrading. That required a bunch of media queries, but but also a fair bit of freedom to eyeball small changes between the key breakpoints. Tracking back and forth between screen sizes gave him a sense of where content would break, so he could quickly fix it.

Another important aspect of PE is being as backwards-compatible as possible. Paul chose to use floats over Flexbox because he felt it would increase the number of browsers that the site would work on. For the specific layout of the site, this turned out to be no problem at all. If he needed Flexbox he would’ve used PE to add it on.

FLIP is taking advantage of user's perception by prioritizing the animation.
FLIP is taking advantage of user's perception by prioritizing the animation.

A major challenge of the site was the card expand and collapse feature, which required thinking up a whole new way to do the animations work. Paul came up with a strategy he calls FLIP, which involves setting animating elements to their final state. From there, you apply compositor-friendly properties like transforms and opacity to invert the changes and return the element to its start position. Finally, with that done, enable transitions on transforms and opacity, and remove those changes. This causes the elements to move to their final positions once more! Paul admits it’s a little unexpected, but it works super well and gives you a performance boost.


Knowing Paul Lewis as the performance guru he is, I wasn't surprised to find out that powerformance was a super important consideration when building the site. He heavily relied on WebPageTest to get the Speed Index value as low as he could. Without the YouTube embed, Paul managed to get it to less than 1,000 on a cable connection, which meant that most of the users would get an initial render in under a second.

Most of the work to achieve this was done in Grunt tasks to concatenate, minify, and compress images as much as possible. The site also defers non-essential images to after page load so that actual content is rendered to screen more quickly.

To make the page load time even better, Paul dropped in a service worker. With it, whether you are online or not, a page visit can be served up from cache, ensuring that you get to the content even on spotty connectivity (extremely important when on conference WiFi!). The CDS site is one of the first production sites to use the new feature, which had Paul run into a bunch of “early adopter issues”, but the huge performance boost, he told me, made up for it. In fact, he's now taking it to every site he builds!

Performance, of course, isn’t just how well a site loads, but also how well it runs. Paul knew the animations were going to be a challenge, which is why he came up with FLIP. Besides that, he went out of his way to ensure that nothing got in the way of touch input or scrolling. Despite the fact that the site isn’t a hugely complex one, he adopted a modified RAIL methodology for the build (he didn’t really need much Idle time), and it helped a bunch!


Since the site was forged by a single person, it meant that Paul was both the designer and developer on the project, resulting in unprecedented levels of understanding regarding each others’ concerns in the two 'teams'. He likes to design desktop down (the opposite of progressive enhancement, which he used during development), because it gives him a sense of what needs to go into the project. Afterwards Paul drops down to the mobile view, which allows him to refine things significantly, and make sure that the most important things are getting the most attention. That then informs the Desktop version, because invariably information architecture and priority will need updating.

Design problem

Not all of it went smoothly. The Material Design guidelines at the time weren’t clear about how to make a content site, so there were areas where he fell short. The design also failed to account for the schedule and session information being related, and in the end, the UX meant that people would go to the schedule and be frustrated that they couldn’t get straight to the session information.

That being said said, I think Paul did a tremendous job of transporting the Material Design spec to a content site. and I’m really pleased with the visuals and motion. It has that unique Material Design feel to it, and the information and look encourages interaction and hierarchy.


  • Successfully released the entire site on Github (> 200 stars) to serve as boilerplate and inspiration to web developers.
  • Incorporated the latest and greatest of the web platform: service worker, web manifest and dynamic theme colors. The net effect is something that feels really integrated with the platform when run on Android devices. If added to the user’s home screen, it feels very much like an app they would use, and that’s really cool.
  • ~73.7k page views, 180k clicks to site subsections meant that people actually used and engaged with it, much more than expected.

All in all, a great inspiration for today's web developers and a very successful conference website.