W3C Hackathon TPAC 2025: Kobe Edition

Thank you for joining us for an evening of quick prototyping, fresh ideas, and nerdy prizes. We hope you had a great time building, learning, and sharing in the spirit of making Web standards better.

Explore Projects Event Details

About

An evening of fun awaits, beyond the formal TPAC schedule.

Date & Time

Date: 11 November, 2025 Time: 19:00–22:30 JST

Location

Venue: Room 501/502, International Conference Center, Kobe

Schedule (JST)

19:00 — Check-in & challenge overview
19:30 — Building starts (90 minutes)
21:00 — Submissions close
21:00-22:00 — Lightning demos & voting
22:00 — Prizes & wrap-up

Dinner will be provided throughout the event.

Choose Your Challenge

Pick one track and keep scope tiny. The exact challenges will be revealed closer to the date.

Challenge #1: CSS Playground

Create a wild CSS demo

Put your coding skills to use to build anything that shows off the power (and weirdness) of CSS. Using HTML and JavaScript is fine. AI tools are allowed—just be ready to explain your process.

Challenge #2: Dashboard

Build a small dashboard or visualization

Create something that gathers or presents information in a useful way: could be related to W3C, the Web, or anything you care about. It can be just a concept or a working prototype.

Participation Guidelines

Rules

You have 90 minutes to build or sketch.
Work solo or in a pair.
All work should be created during the hackathon, but reusing your own snippets is fine.
AI tools are allowed—just be ready to explain your process.

Submission Format

Create a GitHub repository for your project.
Include your code + any other materials in the repo.
Post your project in the GH repo Issue thread for the relevant challenge. Include title, hacker(s), description, repo url and a screenshot.

Submission Issues ↗

Submissions

Below are the 17 amazing projects that were created during the event. Congratulations to all the winners and thank you to everyone who participated!

CSS from the Matrix

2nd Place Winner

We don't need no stickin' styles

Visual disability simulation showcase

1st Place Winner

A collection of visual disability simulations using CSS techniques applied to the TPAC 2025 Hackathon web page.

By Giacomo Petri , Shirisha Balusani , Adam Page

View demo View code

TPAC schedule

Old Web is New Again

Who needs JavaScript? Showing CSS slidedecks

a11y-check-chan

2nd Place Winner

Ally - A gentle, accessibility-first path to consensus

Ally is an accessibility-first consensus platform that turns complex discussions into clear, accountable decisions. Teams capture input as structured items: claims, use cases, proposals, implementation notes, and accessibility concerns, then evaluate them with agreement sliders and explicit objections (non-blocking or blocking). A Consensus Health dashboard surfaces what needs attention now: civility index, participation trends, time-to-decision, and objection hotspots. Ally encourages kind collaboration with a tone helper (NVC prompts) and steel-manning before replies, reducing friction while keeping rigor. Outcomes are exported as clean decision records (Markdown/JSON) to drop into GitHub issues and W3C minutes, preserving provenance and accountability. Built for standards work, Ally blends redundancy, resilience, simplicity, and empathy, so groups can make complexity kind and move from discussion to definition.

By Chiara Cerretti

View demo View code