Add accessilbilty check and fixes

scripts/pa11y.sh

@@ -0,0 +1,34 @@
+#!/bin/sh
+# Accessibility check with pa11y-ci, used by CI and for local runs (see README.md).
+# Builds the site into a temporary directory, serves it on localhost and checks every page
+# in the sitemaps except the past events, which are kept as they were.
+set -eu
+
+PA11Y_CI_VERSION=5.0.0
+PORT=${PORT:-8080}
+# Pages that are not checked: past events and the individual news posts.
+EXCLUDE='^http://localhost:[0-9]+/[a-z]+/(37c3|38c3|39c3|eh22|posts/[^/]+)/'
+
+# Use an installed Chrome/Chromium instead of letting Puppeteer download one.
+if [ -z "${PUPPETEER_EXECUTABLE_PATH:-}" ]; then
+  for candidate in /usr/bin/chromium-browser /usr/bin/chromium "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"; do
+    if [ -x "$candidate" ]; then PUPPETEER_EXECUTABLE_PATH=$candidate; break; fi
+  done
+fi
+export PUPPETEER_EXECUTABLE_PATH
+export PUPPETEER_SKIP_DOWNLOAD=1
+
+cd "$(dirname "$0")/.."
+site=$(mktemp -d)
+hugo --quiet --buildFuture --buildDrafts --baseURL "http://localhost:$PORT/" -d "$site"
+python3 -m http.server "$PORT" --bind 127.0.0.1 -d "$site" >/dev/null 2>&1 &
+server=$!
+trap 'kill $server; rm -rf "$site"' EXIT
+sleep 1
+
+status=0
+for lang in de en; do
+  npx --yes "pa11y-ci@$PA11Y_CI_VERSION" --config .pa11yci.json \
+    --sitemap "http://localhost:$PORT/$lang/sitemap.xml" --sitemap-exclude "$EXCLUDE" || status=1
+done
+exit $status