arc42.de Website

Live site is hosted by GitHub Pages, built by GitHub Actions with this repo's own Jekyll 4.3 gems (not the GitHub Pages gem set) — see .github/workflows/.

Status

Uptime stats by UptimeRobot.

Content

• General Info
• Local Development
• Custom CSS
• Form Support
• Spam Protection
• Timeline for Courses
• Credits

How does it work?

General

The site is build and created with Jekyll and Markdown. It uses the MinimalMistakes template, with a few slight modifications

• home.md is the homepage, it's mapped (via permalink) to "/".
• Most content is organized in markdown files under the _pages directory (a convention from Jekyll).

Local development

Prerequisite: local builds run in Docker. You need Docker installed, nothing else — no local Ruby, no local gems.

The build stack is shared with arc42.org-site: the same Dockerfile on Jekyll 4.3 with the gems pinned in this repo's Gemfile. Each repo builds its own image tag (here arc42-de-site:latest), so building one site never overwrites the other's image. Keep Gemfile and Gemfile.lock identical in both repos — when you change one, change the other, otherwise the two sites drift onto different Jekyll/kramdown versions and start rendering the same Markdown differently. Production is built by GitHub Actions from those same gems, not by the GitHub Pages gem set.

Start the dev server:

make dev

Serves the site on http://localhost:4201 (not 0.0.0.0:4201 — Firefox refuses that host) and rebuilds on every file change. The first run builds the image; later runs start it straight away and need no network. The image is rebuilt only when Dockerfile, Gemfile, Gemfile.lock or docker/jekyll-entrypoint.sh changes (a hash of these files sits in an image label). The Ruby base image is pinned by digest and kept in the local image store, so even such a rebuild only re-runs bundle install, not apt-get.

The port is fixed at 4201, not Jekyll's default 4000, so this dev server can run alongside the other arc42 sites' dev servers without a clash — see raw/port-assignment.md in meta.arc42.org for the full assignment. Jekyll binds 4201 inside the container as well as on the host, so its "Server address:" startup banner names the real port. Three places must stay in step: SITE_PORT in the Makefile, the mapping plus --port in docker-compose.yml, and EXPOSE/CMD in the Dockerfile.

All useful targets (make on its own prints this list):

• make dev — start Jekyll locally with live reload on port 4201
• make image — build the Docker image only if its inputs changed (all targets call this)
• make build — force a rebuild of the image arc42-de-site:latest
• make site — generate the static site into _site/ (one-shot build, no server)
• make check-links — run html-proofer over the built _site (internal links, images, HTML)
• make test-theme — build and assert the generated _site is structurally sound (see below)
• make stop — stop and remove the running dev container
• make clean — remove the generated _site only (image and caches stay)
• make distclean — also stop the container and wipe the Jekyll/Sass cache volumes (image stays)
• make install / make update — re-run bundle install / bundle update in the image after editing the Gemfile
• make shell — open a shell inside the container
• make logs — tail the dev container's logs

Structural check of the generated site

Run this after changing theme files, layouts, permalinks, or Jekyll configuration:

make test-theme

It builds the site inside the container and then asserts things html-proofer does not look at. It fails if the Jekyll log shows a remote-theme fetch or a missing Liquid include/layout, or if representative generated pages are absent — _site/index.html, _site/overview/index.html, _site/termine/index.html, _site/about/index.html, _site/articles/index.html, _site/recommendations/index.html, _site/gallery/index.html, _site/videos/index.html, _site/publikationen/index.html, _site/publikationen/arc42-in-aktion/index.html, _site/sitemap.xml.

Internal page routes use directory-style URLs with trailing slashes, for example permalink: /imprint/ and links such as /imprint/. This keeps local Jekyll development, GitHub Actions, and generated links aligned. make test-theme also fails if a change reintroduces top-level name.html page output, generated internal links without the trailing slash, stale sitemap URLs, or same-site navigation links pointing at 0.0.0.0, www.arc42.de, or absolute https://arc42.de/... anchors.

Updating the vendored theme

The site vendors Minimal Mistakes 4.24.0 locally instead of using remote_theme. To update the theme later:

1. Download the exact upstream Minimal Mistakes release you want to use.
2. Copy upstream additions into _layouts, _includes, _sass, _data, and assets/js.
3. Preserve local overrides such as _includes/head.html, _includes/masthead.html, _includes/footer.html, custom timeline includes, custom feature-row includes, and assets/css/main.scss.
4. Run make clean && make test-theme, then smoke-check /, /overview/, /termine/, /about/, /publikationen/, /gallery/, and /search/.

Custom css

• The timeline (in /termine/) is based upon w3schools
  • We configure the timeline with yaml.
• Some buttons are also based upon w3schools definition.

Custom css is located in /assets/css, the required import statement in /assets/css/main.scss

Registration ("Anmeldung")

Registration lives on trainings.arc42.org (own registration service). arc42.de only links there (https://trainings.arc42.org/anmeldung/?kurs=…&via=arc42.de); _redirects forwards the old /anmeldung/ and /anmeldungEN/ URLs. The former Formspark/Botpoison form was removed in October 2026.

Timeline for Courses

The /termine/ page uses a modular timeline system for easy course management:

Adding/Updating Courses

Edit the courses: array in _pages/termine.md front matter:

courses:
  - type: "msa"                    # Course type: msa, msa_online, req4arc, improve, adoc
    date: "2.-5. Dezember 2025"    # Course dates
    location: "München"            # Location (omit for online courses)
    anchor_id: "msa-dec-2025"      # Unique ID for deep linking
    sold_out: true                 # Optional: marks course as sold out
    few_seats: "Nur noch wenige Plätze verfügbar"  # Optional: warning for limited availability
    pricing: "Frühbucherpreis: €2690"  # Optional: custom pricing text

CAREFUL: This configuration is based upon YAML, and is therefore sensitive to spaces and tabs. Ensure you use EXACTLY four spaces for indentation. Otherwise you will waste precious lifetime debugging yaml.

Deep Linking

Each course gets a unique anchor: https://arc42.de/termine/#msa-dec-2025

Course Types

• msa - German MSA courses (in-person)
• msa_online - English MSA courses (online, Wolfgang Reimesch)
• req4arc - REQ4ARC courses
• improve - IMPROVE courses
• adoc - ADOC courses

The system automatically handles left/right timeline positioning and consistent formatting.

Credits

Site theme

Thanx to Michael Rose, creator of the Minimal-Mistakes Jekyll Theme, follow him on Twitter.

Icons + Images:

• Free images can be found at Unsplash
• I generated the various favicon files with RealFavIconGenerator.

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Licenses

arc42 Template

The arc42 template is licensed under a CreativeCommons Sharealike International 4.0 License.

You are free to:

• Share — copy and redistribute the template in any medium or format
• Adapt — remix, transform, and build upon the material for any purpose, even commercially.

Website Theme: MIT License (MIT)

Copyright (c) 2016ff Michael Rose

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.