Prevent sole admin from deleting their account

Without this guard, the last admin in the system could delete their own
account, making the application unmanageable. This adds a model method
`User#sole_admin?`, a controller guard in `RegistrationsController#destroy`,
and disables the delete button in the profile edit view when the current
user is the only remaining admin.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Gemfile

@@ -1,7 +1,7 @@
 source "https://rubygems.org"
 
 # The requirement for the Ruby version comes from Rails
-gem "rails", "~> 7.2.2"
+gem "rails", "~> 7.2.3"
 gem "sprockets-rails"
 gem "puma", "~> 6.0"
 gem "sassc-rails"
@@ -42,4 +42,11 @@ group :test do
   # Use system testing [https://guides.rubyonrails.org/testing.html#system-testing]
   gem "capybara"
   gem "selenium-webdriver"
+
+  # Remove minitest version restriction after error fixed:
+  #   railties-7.2.3/lib/rails/test_unit/line_filtering.rb:7:in `run':
+  #     wrong number of arguments (given 3, expected 1..2) (ArgumentError)
+  #   from /var/www/.gem/ruby/3.3.0/gems/minitest-6.0.2/lib/minitest.rb:473:in
+  #     `block (2 levels) in run_suite'
+  gem "minitest", "< 6"
 end

Gemfile.lock

@@ -1,66 +1,68 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    actioncable (7.2.2.1)
-      actionpack (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    actioncable (7.2.3)
+      actionpack (= 7.2.3)
+      activesupport (= 7.2.3)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
       zeitwerk (~> 2.6)
-    actionmailbox (7.2.2.1)
-      actionpack (= 7.2.2.1)
-      activejob (= 7.2.2.1)
-      activerecord (= 7.2.2.1)
-      activestorage (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    actionmailbox (7.2.3)
+      actionpack (= 7.2.3)
+      activejob (= 7.2.3)
+      activerecord (= 7.2.3)
+      activestorage (= 7.2.3)
+      activesupport (= 7.2.3)
       mail (>= 2.8.0)
-    actionmailer (7.2.2.1)
-      actionpack (= 7.2.2.1)
-      actionview (= 7.2.2.1)
-      activejob (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    actionmailer (7.2.3)
+      actionpack (= 7.2.3)
+      actionview (= 7.2.3)
+      activejob (= 7.2.3)
+      activesupport (= 7.2.3)
       mail (>= 2.8.0)
       rails-dom-testing (~> 2.2)
-    actionpack (7.2.2.1)
-      actionview (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    actionpack (7.2.3)
+      actionview (= 7.2.3)
+      activesupport (= 7.2.3)
+      cgi
       nokogiri (>= 1.8.5)
       racc
-      rack (>= 2.2.4, < 3.2)
+      rack (>= 2.2.4, < 3.3)
       rack-session (>= 1.0.1)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
       useragent (~> 0.16)
-    actiontext (7.2.2.1)
-      actionpack (= 7.2.2.1)
-      activerecord (= 7.2.2.1)
-      activestorage (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    actiontext (7.2.3)
+      actionpack (= 7.2.3)
+      activerecord (= 7.2.3)
+      activestorage (= 7.2.3)
+      activesupport (= 7.2.3)
       globalid (>= 0.6.0)
       nokogiri (>= 1.8.5)
-    actionview (7.2.2.1)
-      activesupport (= 7.2.2.1)
+    actionview (7.2.3)
+      activesupport (= 7.2.3)
       builder (~> 3.1)
+      cgi
       erubi (~> 1.11)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
-    activejob (7.2.2.1)
-      activesupport (= 7.2.2.1)
+    activejob (7.2.3)
+      activesupport (= 7.2.3)
       globalid (>= 0.3.6)
-    activemodel (7.2.2.1)
-      activesupport (= 7.2.2.1)
-    activerecord (7.2.2.1)
-      activemodel (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    activemodel (7.2.3)
+      activesupport (= 7.2.3)
+    activerecord (7.2.3)
+      activemodel (= 7.2.3)
+      activesupport (= 7.2.3)
       timeout (>= 0.4.0)
-    activestorage (7.2.2.1)
-      actionpack (= 7.2.2.1)
-      activejob (= 7.2.2.1)
-      activerecord (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    activestorage (7.2.3)
+      actionpack (= 7.2.3)
+      activejob (= 7.2.3)
+      activerecord (= 7.2.3)
+      activesupport (= 7.2.3)
       marcel (~> 1.0)
-    activesupport (7.2.2.1)
+    activesupport (7.2.3)
       base64
       benchmark (>= 0.3)
       bigdecimal
@@ -72,15 +74,16 @@ GEM
       minitest (>= 5.1)
       securerandom (>= 0.3)
       tzinfo (~> 2.0, >= 2.0.5)
-    addressable (2.8.7)
-      public_suffix (>= 2.0.2, < 7.0)
-    base64 (0.2.0)
-    bcrypt (3.1.20)
-    benchmark (0.4.0)
-    bigdecimal (3.1.9)
+    addressable (2.8.8)
+      public_suffix (>= 2.0.2, < 8.0)
+    base64 (0.3.0)
+    bcrypt (3.1.21)
+    benchmark (0.5.0)
+    bigdecimal (4.0.1)
     bindex (0.8.1)
     builder (3.3.0)
-    byebug (12.0.0)
+    byebug (13.0.0)
+      reline (>= 0.6.0)
     capybara (3.40.0)
       addressable
       matrix
@@ -90,54 +93,59 @@ GEM
       rack-test (>= 0.6.3)
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
-    concurrent-ruby (1.3.5)
-    connection_pool (2.5.2)
+    cgi (0.5.1)
+    concurrent-ruby (1.3.6)
+    connection_pool (3.0.2)
     crass (1.0.6)
-    date (3.4.1)
-    devise (4.9.4)
+    date (3.5.1)
+    devise (5.0.2)
       bcrypt (~> 3.0)
       orm_adapter (~> 0.1)
-      railties (>= 4.1.0)
+      railties (>= 7.0)
       responders
       warden (~> 1.2.3)
-    drb (2.2.1)
+    drb (2.2.3)
+    erb (6.0.2)
     erubi (1.13.1)
-    ffi (1.17.2-aarch64-linux-gnu)
-    ffi (1.17.2-aarch64-linux-musl)
-    ffi (1.17.2-arm-linux-gnu)
-    ffi (1.17.2-arm-linux-musl)
-    ffi (1.17.2-arm64-darwin)
-    ffi (1.17.2-x86_64-darwin)
-    ffi (1.17.2-x86_64-linux-gnu)
-    ffi (1.17.2-x86_64-linux-musl)
-    globalid (1.2.1)
+    ffi (1.17.3-aarch64-linux-gnu)
+    ffi (1.17.3-aarch64-linux-musl)
+    ffi (1.17.3-arm-linux-gnu)
+    ffi (1.17.3-arm-linux-musl)
+    ffi (1.17.3-arm64-darwin)
+    ffi (1.17.3-x86_64-darwin)
+    ffi (1.17.3-x86_64-linux-gnu)
+    ffi (1.17.3-x86_64-linux-musl)
+    globalid (1.3.0)
       activesupport (>= 6.1)
-    i18n (1.14.7)
+    i18n (1.14.8)
       concurrent-ruby (~> 1.0)
-    importmap-rails (2.1.0)
+    importmap-rails (2.2.3)
       actionpack (>= 6.0.0)
       activesupport (>= 6.0.0)
       railties (>= 6.0.0)
-    io-console (0.8.0)
-    irb (1.15.2)
+    io-console (0.8.2)
+    irb (1.17.0)
       pp (>= 0.6.0)
+      prism (>= 1.3.0)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
     logger (1.7.0)
-    loofah (2.24.0)
+    loofah (2.25.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.12.0)
-    mail (2.8.1)
+    mail (2.9.0)
+      logger
       mini_mime (>= 0.1.1)
       net-imap
       net-pop
       net-smtp
-    marcel (1.0.4)
-    matrix (0.4.2)
+    marcel (1.1.0)
+    matrix (0.4.3)
     mini_mime (1.1.5)
-    minitest (5.25.5)
-    mysql2 (0.5.6)
-    net-imap (0.5.7)
+    minitest (5.27.0)
+    mysql2 (0.5.7)
+      bigdecimal
+    net-imap (0.6.3)
       date
       net-protocol
     net-pop (0.1.2)
@@ -146,83 +154,94 @@ GEM
       timeout
     net-smtp (0.5.1)
       net-protocol
-    nio4r (2.7.4)
-    nokogiri (1.18.8-aarch64-linux-gnu)
+    nio4r (2.7.5)
+    nokogiri (1.19.1-aarch64-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.18.8-aarch64-linux-musl)
+    nokogiri (1.19.1-aarch64-linux-musl)
       racc (~> 1.4)
-    nokogiri (1.18.8-arm-linux-gnu)
+    nokogiri (1.19.1-arm-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.18.8-arm-linux-musl)
+    nokogiri (1.19.1-arm-linux-musl)
       racc (~> 1.4)
-    nokogiri (1.18.8-arm64-darwin)
+    nokogiri (1.19.1-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.8-x86_64-darwin)
+    nokogiri (1.19.1-x86_64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.8-x86_64-linux-gnu)
+    nokogiri (1.19.1-x86_64-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.18.8-x86_64-linux-musl)
+    nokogiri (1.19.1-x86_64-linux-musl)
       racc (~> 1.4)
     orm_adapter (0.5.0)
-    pg (1.5.9)
-    pp (0.6.2)
+    pg (1.6.3)
+    pg (1.6.3-aarch64-linux)
+    pg (1.6.3-aarch64-linux-musl)
+    pg (1.6.3-arm64-darwin)
+    pg (1.6.3-x86_64-darwin)
+    pg (1.6.3-x86_64-linux)
+    pg (1.6.3-x86_64-linux-musl)
+    pp (0.6.3)
       prettyprint
     prettyprint (0.2.0)
-    psych (5.2.3)
+    prism (1.9.0)
+    psych (5.3.1)
       date
       stringio
-    public_suffix (6.0.1)
-    puma (6.6.0)
+    public_suffix (7.0.2)
+    puma (6.6.1)
       nio4r (~> 2.0)
     racc (1.8.1)
-    rack (3.1.13)
-    rack-session (2.1.0)
+    rack (3.2.5)
+    rack-session (2.1.1)
       base64 (>= 0.1.0)
       rack (>= 3.0.0)
     rack-test (2.2.0)
       rack (>= 1.3)
-    rackup (2.2.1)
+    rackup (2.3.1)
       rack (>= 3)
-    rails (7.2.2.1)
-      actioncable (= 7.2.2.1)
-      actionmailbox (= 7.2.2.1)
-      actionmailer (= 7.2.2.1)
-      actionpack (= 7.2.2.1)
-      actiontext (= 7.2.2.1)
-      actionview (= 7.2.2.1)
-      activejob (= 7.2.2.1)
-      activemodel (= 7.2.2.1)
-      activerecord (= 7.2.2.1)
-      activestorage (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    rails (7.2.3)
+      actioncable (= 7.2.3)
+      actionmailbox (= 7.2.3)
+      actionmailer (= 7.2.3)
+      actionpack (= 7.2.3)
+      actiontext (= 7.2.3)
+      actionview (= 7.2.3)
+      activejob (= 7.2.3)
+      activemodel (= 7.2.3)
+      activerecord (= 7.2.3)
+      activestorage (= 7.2.3)
+      activesupport (= 7.2.3)
       bundler (>= 1.15.0)
-      railties (= 7.2.2.1)
-    rails-dom-testing (2.2.0)
+      railties (= 7.2.3)
+    rails-dom-testing (2.3.0)
       activesupport (>= 5.0.0)
       minitest
       nokogiri (>= 1.6)
-    rails-html-sanitizer (1.6.2)
-      loofah (~> 2.21)
+    rails-html-sanitizer (1.7.0)
+      loofah (~> 2.25)
       nokogiri (>= 1.15.7, != 1.16.7, != 1.16.6, != 1.16.5, != 1.16.4, != 1.16.3, != 1.16.2, != 1.16.1, != 1.16.0.rc1, != 1.16.0)
-    railties (7.2.2.1)
-      actionpack (= 7.2.2.1)
-      activesupport (= 7.2.2.1)
+    railties (7.2.3)
+      actionpack (= 7.2.3)
+      activesupport (= 7.2.3)
+      cgi
       irb (~> 1.13)
       rackup (>= 1.0.0)
       rake (>= 12.2)
       thor (~> 1.0, >= 1.2.2)
+      tsort (>= 0.2)
       zeitwerk (~> 2.6)
-    rake (13.2.1)
-    rdoc (6.13.1)
+    rake (13.3.1)
+    rdoc (7.2.0)
+      erb
       psych (>= 4.0.0)
-    regexp_parser (2.10.0)
-    reline (0.6.1)
+      tsort
+    regexp_parser (2.11.3)
+    reline (0.6.3)
       io-console (~> 0.5)
-    responders (3.1.1)
-      actionpack (>= 5.2)
-      railties (>= 5.2)
-    rexml (3.4.1)
-    rubyzip (2.4.1)
+    responders (3.2.0)
+      actionpack (>= 7.0)
+      railties (>= 7.0)
+    rexml (3.4.4)
+    rubyzip (3.2.2)
     sassc (2.4.0)
       ffi (~> 1.9)
     sassc-rails (2.1.2)
@@ -232,11 +251,11 @@ GEM
       sprockets-rails
       tilt
     securerandom (0.4.1)
-    selenium-webdriver (4.31.0)
+    selenium-webdriver (4.41.0)
       base64 (~> 0.2)
       logger (~> 1.4)
       rexml (~> 3.2, >= 3.2.5)
-      rubyzip (>= 1.2.2, < 3.0)
+      rubyzip (>= 1.2.2, < 4.0)
       websocket (~> 1.0)
     sprockets (4.2.2)
       concurrent-ruby (~> 1.0)
@@ -246,19 +265,20 @@ GEM
       actionpack (>= 6.1)
       activesupport (>= 6.1)
       sprockets (>= 3.0.0)
-    sqlite3 (2.7.3-aarch64-linux-gnu)
-    sqlite3 (2.7.3-aarch64-linux-musl)
-    sqlite3 (2.7.3-arm-linux-gnu)
-    sqlite3 (2.7.3-arm-linux-musl)
-    sqlite3 (2.7.3-arm64-darwin)
-    sqlite3 (2.7.3-x86_64-darwin)
-    sqlite3 (2.7.3-x86_64-linux-gnu)
-    sqlite3 (2.7.3-x86_64-linux-musl)
-    stringio (3.1.7)
-    thor (1.3.2)
-    tilt (2.6.0)
-    timeout (0.4.3)
-    turbo-rails (2.0.13)
+    sqlite3 (2.9.0-aarch64-linux-gnu)
+    sqlite3 (2.9.0-aarch64-linux-musl)
+    sqlite3 (2.9.0-arm-linux-gnu)
+    sqlite3 (2.9.0-arm-linux-musl)
+    sqlite3 (2.9.0-arm64-darwin)
+    sqlite3 (2.9.0-x86_64-darwin)
+    sqlite3 (2.9.0-x86_64-linux-gnu)
+    sqlite3 (2.9.0-x86_64-linux-musl)
+    stringio (3.2.0)
+    thor (1.5.0)
+    tilt (2.7.0)
+    timeout (0.6.0)
+    tsort (0.2.0)
+    turbo-rails (2.0.23)
       actionpack (>= 7.1.0)
       railties (>= 7.1.0)
     tzinfo (2.0.6)
@@ -272,13 +292,13 @@ GEM
       bindex (>= 0.4.0)
       railties (>= 6.0.0)
     websocket (1.2.11)
-    websocket-driver (0.7.7)
+    websocket-driver (0.8.0)
       base64
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
     xpath (3.2.0)
       nokogiri (~> 1.8)
-    zeitwerk (2.7.2)
+    zeitwerk (2.7.5)
 
 PLATFORMS
   aarch64-linux-gnu
@@ -295,10 +315,11 @@ DEPENDENCIES
   capybara
   devise
   importmap-rails
+  minitest (< 6)
   mysql2 (~> 0.5)
   pg (~> 1.5)
   puma (~> 6.0)
-  rails (~> 7.2.2)
+  rails (~> 7.2.3)
   sassc-rails
   selenium-webdriver
   sprockets-rails

app/assets/images/pictograms/chevron-down.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path d="M7.41,8.58L12,13.17L16.59,8.58L18,10L12,16L6,10L7.41,8.58Z" /></svg>

app/assets/stylesheets/application.css

@@ -15,6 +15,13 @@
  *= require_self
  */
 
+/* Strive for simplicity:
+ * * style elements/tags only - if possible,
+ * * replace element/tag name with class name - if element has to be styled
+ * differently depending on context (e.g. form)
+ *
+ * NOTE: Style in a modular way, similar to how CSS @scope would be used,
+ * to make transition easier once @scope is widely available */
 :root {
   --color-focus-gray: #f3f3f3;
   --color-border-gray: #dddddd;
@@ -48,37 +55,24 @@
 }
 
 
-/* TODO: collapse gaps around empty rows (`topside`) once possible
- * https://github.com/w3c/csswg-drafts/issues/5813 */
-body {
-  display: grid;
-  gap: 0.8em;
-  grid-template-areas:
-    "header    header  header"
-    "nav       nav     nav"
-    "leftside  topside rightside"
-    "leftside  main    rightside";
-  grid-template-columns: 1fr auto 1fr;
-  grid-template-rows: repeat(4, auto);
-  font-family: system-ui;
-  margin: 0.4em;
-}
+/* Color coding of input controls' background:
+ *  blue - target for interaction with pointer
+ *  gray - target for interaction with keyboard
+ *  red - destructive, non-undoable action
+ */
 button,
+details,
 input,
 select,
 textarea {
   background-color: inherit;
   font: inherit;
 }
+details,
 input,
 select {
   text-align: inherit;
 }
-
-
-/* blue - target for interaction with pointer */
-/* gray - target for interaction with keyboard */
-/* TODO: remove non-font-size rems from buttons/inputs below */
 a,
 button,
 input[type=submit] {
@@ -101,11 +95,12 @@ input[type=submit]:not([hidden]),
 button,
 input[type=submit] {
   font-size: 0.8rem;
-  padding: 0.4em;
+  padding: 0.6em 0.5em;
   width: fit-content;
 }
 input:not([type=submit]):not([type=checkbox]),
 select,
+summary,
 textarea {
   padding: 0.2em 0.4em;
 }
@@ -113,68 +108,23 @@ textarea {
 button,
 input,
 select,
+summary,
 textarea {
   border: solid 1px var(--color-gray);
   border-radius: 0.25em;
 }
-fieldset,
+input[type=checkbox],
+svg,
 textarea {
   margin: 0
 }
-.button > svg,
-.tab > svg,
-button > svg {
-  height: 1.8em;
-  width: 1.8em;
-}
-.button > svg:not(:last-child),
-.tab > svg:not(:last-child),
-button > svg:not(:last-child) {
-  padding-right: 0.4em;
-}
-fieldset {
-  padding: 0.4em;
-}
-legend {
-  color: var(--color-gray);
-  display: flex;
-  gap: 0.4em;
-  width: 100%;
-}
-legend span {
-  align-content: center;
-  flex-grow: 1;
-}
-
-/* TODO: move normal non-button links (<a>:hover/:focus) styling here (i.e.
- * page-wide, top-level) and remove from table.items - as the style should be
- * same everywhere */
-.button:focus-visible,
-button:focus-visible,
-input[type=submit]:focus-visible {
-  background-color: var(--color-focus-gray);
-}
-.button:hover,
-button:hover,
-input[type=submit]:hover {
-  background-color: var(--color-blue);
-  border-color: var(--color-blue);
-  color: white;
-  fill: white;
-}
-.dangerous:hover {
-  background-color: var(--color-red);
-  border-color: var(--color-red);
-}
-
 input[type=checkbox] {
   accent-color: var(--color-blue);
   appearance: none;
   -webkit-appearance: none;
   display: flex;
-  height: 1.1rem;
-  margin: 0;
-  width: 1.1rem;
+  height: 1.1em;
+  width: 1.1em;
 }
 input[type=checkbox]:checked {
   appearance: checkbox;
@@ -192,42 +142,96 @@ input::-webkit-outer-spin-button {
   -webkit-appearance: none;
   margin: 0;
 }
+.button > svg,
+.tab > svg,
+button > svg {
+  height: 1.4em;
+  width: 1.4em;
+}
+.button > svg:not(:last-child),
+.tab > svg:not(:last-child),
+button > svg:not(:last-child) {
+  margin-right: 0.2em;
+}
+/* TODO: move normal non-button links (<a>:hover/:focus) styling here (i.e.
+ * page-wide, top-level) and remove from table.items - as the style should be
+ * same everywhere */
+.button:focus-visible,
+button:focus-visible,
+input[type=submit]:focus-visible {
+  background-color: var(--color-focus-gray);
+}
+input:focus-visible,
+select:focus-visible,
+select:focus-within,
+/* TODO: how to achieve summary:focus-within for ::details-content? */
+summary:focus-visible,
+textarea:focus-visible {
+  accent-color: var(--color-dark-blue);
+  background-color: var(--color-focus-gray);
+}
+.button:hover,
+button:hover,
+input[type=submit]:hover {
+  background-color: var(--color-blue);
+  border-color: var(--color-blue);
+  color: white;
+  fill: white;
+}
+.dangerous:hover {
+  background-color: var(--color-red);
+  border-color: var(--color-red);
+}
 input:hover,
 select:hover,
+summary:hover,
 textarea:hover {
   border-color: var(--color-blue);
   outline: solid 1px var(--color-blue);
 }
+select:hover,
+summary:hover {
+  cursor: pointer;
+}
 input:invalid,
 select:invalid,
 textarea:invalid {
   border-color: var(--color-red);
   outline: solid 1px var(--color-red);
 }
-select:hover {
-  cursor: pointer;
-}
-input:focus-visible,
-select:focus-within,
-select:focus-visible,
-textarea:focus-visible {
-  accent-color: var(--color-dark-blue);
-  background-color: var(--color-focus-gray);
-}
-fieldset,
 input[type=text]:read-only,
 textarea:read-only {
   border: none;
-  padding-left: 0;
-  padding-right: 0;
+  padding-inline: 0;
 }
 
 
+/* NOTE: collapse gaps around empty rows (`topside`) once possible
+ * with grid-collapse property and remove alternative grid-template
+ * https://github.com/w3c/csswg-drafts/issues/5813 */
+body {
+  display: grid;
+  gap: 0.8em;
+  grid-template-areas:
+    "header    header  header"
+    "nav       nav     nav"
+    "leftside  topside rightside"
+    "leftside  main    rightside";
+  grid-template-columns: 1fr minmax(max-content, 2fr) 1fr;
+  font-family: system-ui;
+  margin: 0.4em;
+}
+body:not(:has(.topside-area)) {
+  grid-template-areas:
+    "header    header  header"
+    "nav       nav     nav"
+    "leftside  main    rightside";
+}
+
 header {
   grid-area: header;
 }
 
-
 .navigation {
   display: flex;
   grid-area: nav;
@@ -240,7 +244,7 @@ header {
   flex: 1;
   font-size: 1rem;
   justify-content: center;
-  padding-block: 0.3em;
+  padding-block: 0.4em;
 }
 .navigation > .tab:hover,
 .navigation > .tab:focus-visible {
@@ -252,21 +256,19 @@ header {
   fill: var(--color-blue);
 }
 
-
-.topside {
+.topside-area {
   grid-area: topside;
 }
-.leftside {
+.leftside-area {
   grid-area: leftside;
 }
-.main {
+.main-area {
   grid-area: main;
 }
-.rightside {
+.rightside-area {
   grid-area: rightside;
 }
 
-
 .buttongrid {
   display: grid;
   gap: 0.4em;
@@ -274,7 +276,7 @@ header {
   grid-template-columns: auto 1fr auto;
   grid-template-rows: max-content;
 }
-.tools {
+.tools-area {
   grid-area: tools;
 }
 
@@ -338,47 +340,43 @@ header {
   opacity: 1;
 }
 
-
-/* TODO: Update styling, including rem removal. */
-form table {
-  border-spacing: 0.8rem;
+/* TODO: Hover over invalid should work like in measurements (thin vs thick border) */
+.labeled-form {
+  align-items: center;
+  display: grid;
+  gap: 0.9em 1.1em;
+  grid-template-columns: 1fr minmax(max-content, 0.5fr) 1fr;
 }
-form tr td:first-child {
+.labeled-form label {
   color: var(--color-gray);
   font-size: 0.9rem;
-  padding-right: 0.25rem;
+  grid-column: 1;
   text-align: right;
+  white-space: nowrap;
 }
-form label.required {
+.labeled-form label.required {
   font-weight: bold;
 }
-form label.error,
-form td.error::after {
+/* Don't style `label.error + input` if case already covered by input:invalid */
+.labeled-form label.error {
   color: var(--color-red);
 }
-form td.error {
-  display: -webkit-box;
-}
-form td.error::after {
-  content: attr(data-content);
-  font-size: 0.9rem;
-  margin-left: 1rem;
-  padding: 0.25rem 0;
-  position: absolute;
-}
-form em {
+.labeled-form em {
   color: var(--color-text-gray);
   font-size: 0.75rem;
   font-weight: normal;
 }
-form input[type=submit] {
-  float: none;
+.labeled-form input {
+  grid-column: 2;
+}
+.labeled-form input[type=submit] {
   font-size: 1rem;
-  margin: 1.5rem auto 0 auto;
-  padding: 0.75rem;
+  margin: 1.5em auto 0 auto;
+  padding: 0.75em;
 }
 
 
+/* TODO: remove .items class (?) and make 'form table' work properly */
 table.items {
   border-spacing: 0;
   border: solid 1px var(--color-border-gray);
@@ -386,6 +384,9 @@ table.items {
   font-size: 0.85rem;
   text-align: left;
 }
+table:not(:has(tr)) {
+  display: none;
+}
 table.items thead {
   font-size: 0.8rem;
 }
@@ -462,7 +463,7 @@ table.items tr.form td {
 }
 
 /* TODO: replace :hover:focus-visible combos with proper LOVE stye order */
-/* TODO: Update styling, including rem removal. */
+/* TODO: Update table styling: simplify selectors, deduplicate, remove non-font rem. */
 table.items td.link a:hover,
 table.items td.link a:focus-visible,
 table.items td.link a:hover:focus-visible {
@@ -485,15 +486,13 @@ table.items td:not(:first-child),
   color: var(--color-table-gray);
   fill: var(--color-table-gray);
 }
-table.items td.hint {
-  color: var(--color-table-gray);
-  font-style: italic;
-  font-size: 0.8rem;
-  padding: 1em;
-}
 table.items svg {
-  height: 1.2rem;
+  height: 1rem;
   vertical-align: middle;
+  width: 1rem;
+}
+table.items svg:last-child {
+  height: 1.2rem;
   width: 1.2rem;
 }
 table.items td.svg {
@@ -506,7 +505,8 @@ table.items .button,
 table.items button,
 table.items input[type=submit] {
   font-weight: normal;
-  padding: 0.3em;
+  height: 100%;
+  padding: 0.4em;
 }
 table.items input:not([type=submit]):not([type=checkbox]),
 table.items select,
@@ -532,7 +532,6 @@ table.items select:focus-within,
 table.items select:focus-visible {
   color: black;
 }
-
 form a[name=cancel] {
   border-color: var(--color-border-gray);
   color: var(--color-nav-gray);
@@ -550,21 +549,31 @@ form table.items td:first-child {
   color: inherit;
 }
 
+
 .centered {
   margin: 0 auto;
 }
 .extendedright {
   margin-right: auto;
 }
+.hexpand {
+  width: 100%;
+}
 .hflex {
   display: flex;
   gap: 0.8em;
 }
+.hflex.reverse {
+  flex-direction: row-reverse;
+}
 .hflex.centered {
   justify-content: center;
 }
-.vexpand {
-  width: 100%;
+.hint {
+  color: var(--color-table-gray);
+  font-style: italic;
+  font-size: 0.9rem;
+  text-align: center;
 }
 .vflex {
   display: flex;
@@ -572,12 +581,81 @@ form table.items td:first-child {
   flex-direction: column;
 }
 [disabled] {
+/* label:has(input[disabled]) {
+ * TODO: disabled checkbox blue square focus removal; disabled label styling;
+ * focused label styling (currently only checkbox has focus)
+ * */
   border-color: var(--color-border-gray) !important;
   color: var(--color-border-gray) !important;
   cursor: not-allowed;
   fill: var(--color-border-gray) !important;
   pointer-events: none;
 }
-.unwrappable {
+
+
+details {
+  align-content: center;
+  position: relative;
+}
+summary {
+  align-items: center;
+  color: var(--color-gray);
+  display: flex;
+  gap: 0.2em;
+  height: 100%;
   white-space: nowrap;
 }
+summary::before {
+  background-color: #000;
+  content: "";
+  height: 1em;
+  mask-image: url('pictograms/chevron-down.svg');
+  mask-size: cover;
+  width: 1em;
+}
+summary:has(.button) {
+  padding-block: 0;
+  padding-inline-end: 0;
+}
+summary .button {
+  border: solid 1px var(--color-border-gray);
+  border-radius: inherit;
+  border-top-left-radius: 0;
+  border-bottom-left-radius: 0;
+  border-style: none none none solid;
+  height: 100%;
+}
+summary span {
+  width: 100%;
+}
+details[open] summary::before {
+  transform: rotate(180deg);
+}
+summary::marker {
+  padding-left: 0.25em;
+}
+/* NOTE: use details[open]::details-content once widely available */
+details[open] ul {
+  background: white;
+  border: solid 1px var(--color-border-gray);
+  border-radius: 0.25em;
+  box-shadow: 1px 1px 3px var(--color-border-gray);
+  margin: -1px 0 0 0;
+  padding-left: 0;
+  position: absolute;
+  width: 100%;
+}
+li:hover {
+  background-color: var(--color-focus-gray);
+}
+li label {
+  align-items: center;
+  display: flex;
+  line-height: 1.4em;
+}
+li input[type=checkbox] {
+  margin: 0 0.25em;
+}
+li::marker {
+  content: '';
+}

app/controllers/application_controller.rb

@@ -9,6 +9,7 @@ class ApplicationController < ActionController::Base
   helper_method :current_user_disguised?
   helper_method :current_tab
 
+  before_action :redirect_to_setup_if_needed
   before_action :authenticate_user!
 
   class AccessForbidden < StandardError; end
@@ -43,6 +44,16 @@ class ApplicationController < ActionController::Base
 
   private
 
+  # Redirect to the web setup wizard when the application has not yet been
+  # initialised (i.e. no admin account exists in the database).
+  def redirect_to_setup_if_needed
+    return if User.exists?(status: :admin)
+    redirect_to new_setup_path
+  rescue ActiveRecord::StatementInvalid
+    # Tables may not exist yet (migrations not run). Fall through and let the
+    # normal request handling surface a meaningful error.
+  end
+
   def render_no_content(record)
     helpers.render_errors(record)
     render html: nil, layout: true

app/controllers/readouts_controller.rb

@@ -1,23 +1,16 @@
 class ReadoutsController < ApplicationController
-  before_action :find_quantity, only: [:new, :discard]
+  before_action :find_quantities, only: [:new]
+  before_action :find_quantity, only: [:discard]
   before_action :find_prev_quantities, only: [:new, :discard]
 
   def new
-    new_quantities =
-      case params[:button]
-      when 'children'
-        @quantity.subquantities
-      when 'subtree'
-        @quantity.progenies
-      else
-        [@quantity]
-      end
-    new_quantities -= @prev_quantities
-    @readouts = current_user.readouts.build(new_quantities.map { |q| {quantity: q} })
+    @quantities -= @prev_quantities
+    # TODO: raise ParameterInvalid if new_quantities.empty?
+    @readouts = current_user.readouts.build(@quantities.map { |q| {quantity: q} })
 
     @user_units = current_user.units.ordered
 
-    quantities = @prev_quantities + new_quantities
+    quantities = @prev_quantities + @quantities
     @superquantity = current_user.quantities
       .common_ancestors(quantities.map(&:parent_id)).first
   end
@@ -31,6 +24,10 @@ class ReadoutsController < ApplicationController
 
   private
 
+  def find_quantities
+    @quantities = current_user.quantities.find(params[:quantity])
+  end
+
   def find_quantity
     @quantity = current_user.quantities.find_by!(id: params[:id])
   end

app/controllers/registrations_controller.rb

@@ -1,8 +1,26 @@
 class RegistrationsController < Devise::RegistrationsController
   before_action :authenticate_user!, only: [:edit, :update, :destroy]
 
+  def destroy
+    if current_user.sole_admin?
+      redirect_back fallback_location: edit_user_registration_path,
+        alert: t(".sole_admin")
+      return
+    end
+    super
+  end
+
   protected
 
+  def build_resource(hash = {})
+    super
+    # Skip the email confirmation step when the admin has enabled this option
+    # via the web setup wizard (stored as the "skip_email_confirmation" Setting).
+    # The account becomes active immediately so the user can sign in right after
+    # registering.
+    resource.skip_confirmation! if Setting.get("skip_email_confirmation") == "true"
+  end
+
   def update_resource(resource, params)
     # Based on update_with_password()
     if params[:password].blank?

app/controllers/setup_controller.rb

@@ -0,0 +1,59 @@
+# Handles the one-time web-based installation wizard.
+#
+# The wizard is only accessible when no admin account exists yet.  Once an
+# admin has been created the controller redirects every request to the root
+# path, so it can never be used to overwrite an existing installation.
+class SetupController < ActionController::Base
+  # Use the full application layout (header, flash, etc.) so the page looks
+  # consistent with the rest of the site.
+  layout "application"
+
+  before_action :redirect_if_installed
+
+  def new
+  end
+
+  def create
+    email    = params[:admin_email].to_s.strip
+    password = params[:admin_password].to_s
+    confirm  = params[:admin_password_confirmation].to_s
+
+    errors = []
+    errors << t(".email_blank")    if email.blank?
+    errors << t(".password_blank") if password.blank?
+    errors << t(".password_mismatch") if password != confirm
+
+    if errors.any?
+      flash.now[:alert] = errors.join("  ")
+      return render :new, status: :unprocessable_entity
+    end
+
+    user = User.new(email: email, password: password, status: :admin)
+    user.skip_confirmation!
+
+    unless user.save
+      flash.now[:alert] = user.errors.full_messages.join("  ")
+      return render :new, status: :unprocessable_entity
+    end
+
+    # Persist runtime settings chosen during setup.
+    Setting.set("skip_email_confirmation",
+                params[:skip_email_confirmation] == "1")
+
+    # Optionally seed the built-in default units.
+    if params[:seed_units] == "1"
+      load Rails.root.join("db/seeds/units.rb")
+    end
+
+    redirect_to new_user_session_path, notice: t(".success")
+  end
+
+  private
+
+  def redirect_if_installed
+    redirect_to root_path if User.exists?(status: :admin)
+  rescue ActiveRecord::StatementInvalid
+    # Tables are not yet migrated — stay on the setup page so the user sees a
+    # meaningful error rather than a crash.
+  end
+end

app/helpers/application_helper.rb

@@ -1,59 +1,84 @@
 module ApplicationHelper
-  # TODO: replace legacy content_tag with tag.tagname
-  class LabelledFormBuilder < ActionView::Helpers::FormBuilder
-    (field_helpers - [:label]).each do |selector|
+  class LabeledFormBuilder < ActionView::Helpers::FormBuilder
+    (field_helpers - [:label, :hidden_field]).each do |selector|
       class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
         def #{selector}(method, options = {})
-          labelled_row_for(method, options) { super }
+          labeled_field_for(method, options) { super }
         end
       RUBY_EVAL
     end
 
     def select(method, choices = nil, options = {}, html_options = {})
-      labelled_row_for(method, options) { super }
-    end
-
-    def submit(value, options = {})
-      @template.content_tag :tr do
-        @template.content_tag :td, super, colspan: 2
-      end
-    end
-
-    def form_for(&block)
-      @template.content_tag(:table, class: "centered") { yield(self) } +
-      # Display leftover error messages (there shouldn't be any)
-      @template.content_tag(:div, @object&.errors.full_messages.join(@template.tag(:br)))
+      labeled_field_for(method, options) { super }
     end
 
     private
 
-    def labelled_row_for(method, options)
-      @template.content_tag :tr do
-        @template.content_tag(:td, label_for(method, options), class: "unwrappable") +
-        @template.content_tag(:td, options.delete(:readonly) ? @object.public_send(method) : yield,
-          @object&.errors[method].present? ?
-            {class: "error", data: {content: @object&.errors.delete(method).join(" and ")}} :
-            {})
+    def labeled_field_for(method, options)
+      field = if options.delete(:readonly) then
+                value = object.public_send(method)
+                value = @template.l(value) if value.respond_to?(:strftime)
+                value ||= options[:placeholder]
+              else
+                yield
               end
+      label_for(method, options) + field
     end
 
     def label_for(method, options = {})
-      return '' if options[:label] == false
-
-      text = options.delete(:label)
-      text ||= @object.class.human_attribute_name(method).capitalize
       classes = @template.class_names(required: options[:required],
-                                      error: @object&.errors[method].present?)
-      label = label(method, "#{text}:", class: classes)
-      hint = options.delete(:hint)
+                                      error: object.errors[method].present?)
 
-      label + (@template.tag(:br) + @template.content_tag(:em, hint) if hint)
+      handler = {missing_interpolation_argument_handler: method(:interpolation_missing)}
+      # Label translation search order:
+      #   controller.action.* => helpers.label.model.* => activerecord.attributes.model.*
+      # First 2 levels are translated recursively.
+      label(method, class: classes) do |builder|
+        translation = I18n.config.with(**handler) { deep_translate(method, **options) }
+        translation.presence || "#{builder.translation}:"
       end
     end
 
-  def labelled_form_for(record, options = {}, &block)
-    options = options.deep_merge(builder: LabelledFormBuilder, data: {turbo: false})
-    form_for(record, **options) { |f| f.form_for(&block) }
+    def interpolation_missing(key, values, string)
+      @template.instance_values[key.to_s] || deep_translate(key, **values)
+    end
+
+    # Extension to label text translation:
+    # * recursive translation,
+    # * interpolation of (_relative_) translation key names and instance variables,
+    # * pluralization based on any interpolable value
+    # TODO: add unit tests for the above
+    def deep_translate(key, **options)
+      options[:default] = [
+        :".#{key}",
+        :"helpers.label.#{@object_name}.#{key}_html",
+        :"helpers.label.#{@object_name}.#{key}",
+        ""
+      ]
+
+      # At least 1 interpolation key is required for #translate to act on
+      # missing interpolation arguments (i.e. call custom handler).
+      # Also setting `key` to nil avoids recurrent translation.
+      options[key] = nil
+
+      @template.t(".#{key}_html", **options) do |translation, resolved_key|
+        if translation.is_a?(Array) && (count = translation.to_h[:count])
+          @template.t(resolved_key, count: I18n.interpolate(count, **options), **options)
+        else
+          translation
+        end
+      end
+    end
+  end
+
+  def labeled_form_for(record, options = {}, &block)
+    extra_options = {builder: LabeledFormBuilder,
+                     data: {turbo: false},
+                     html: {class: 'labeled-form'}}
+    options = options.deep_merge(extra_options) do |key, left, right|
+      key == :class ? class_names(left, right) : right
+    end
+    form_for(record, **options, &block)
   end
 
   class TabularFormBuilder < ActionView::Helpers::FormBuilder
@@ -75,12 +100,11 @@ module ApplicationHelper
     end
 
     def number_field(method, options = {})
-      value = object.public_send(method)
-      if value.is_a?(BigDecimal)
-        options[:value] = value.to_scientific
-        type = object.class.type_for_attribute(method)
-        options[:step] ||= BigDecimal(10).power(-type.scale)
-        options[:max] ||= BigDecimal(10).power(type.precision - type.scale) -
+      attr_type = object.type_for_attribute(method)
+      if attr_type.type == :decimal
+        options[:value] = object.public_send(method)&.to_scientific
+        options[:step] ||= BigDecimal(10).power(-attr_type.scale)
+        options[:max] ||= BigDecimal(10).power(attr_type.precision - attr_type.scale) -
           options[:step]
         options[:min] = options[:min] == :step ? options[:step] : options[:min]
         options[:min] ||= -options[:max]
@@ -112,6 +136,7 @@ module ApplicationHelper
     # and the first input gets focus.
     record_object, options = nil, record_object if record_object.is_a?(Hash)
     options.merge!(builder: TabularFormBuilder, skip_default_ids: true)
+    # TODO: set error message with setCustomValidity instead of rendering to flash?
     render_errors(record_object || record_name)
     fields_for(record_name, record_object, **options, &block)
   end
@@ -123,7 +148,7 @@ module ApplicationHelper
   end
 
   def svg_tag(source, label = nil, options = {})
-    svg_tag = content_tag :svg, options do
+    svg_tag = tag.svg(options) do
       tag.use(href: "#{image_path(source + ".svg")}#icon")
     end
     label.blank? ? svg_tag : svg_tag + tag.span(label)
@@ -171,17 +196,23 @@ module ApplicationHelper
 
   def image_link_to_unless_current(name, image = nil, options = nil, html_options = {})
     name, html_options = link_or_button_options(:link, name, image, html_options)
-    html_options = html_options.deep_merge DISABLED_ATTRIBUTES if current_page?(options)
+    # NOTE: Starting from Rails 8.1.0, below condition can be replaced with:
+    #   current_page?(options, method: [:get, :post])
+    if request.path == url_for(options)
+      html_options = html_options.deep_merge DISABLED_ATTRIBUTES
+    end
     link_to name, options, html_options
   end
 
   def render_errors(records)
-    flash[:alert] ||= []
+    # Conversion of flash to Array only required because of Devise
+    flash[:alert] = Array(flash[:alert])
     Array(records).each { |record| flash[:alert] += record.errors.full_messages }
   end
 
   def render_flash_messages
     flash.map do |entry, messages|
+      # Conversion of flash to Array only required because of Devise
       Array(messages).map do |message|
         tag.div class: "flash #{entry}" do
           tag.div(sanitize(message)) + tag.button(sanitize("&times;"), tabindex: -1,
@@ -204,8 +235,6 @@ module ApplicationHelper
   private
 
   def link_or_button_options(type, name, image = nil, html_options)
-    name = svg_tag("pictograms/#{image}", name) if image
-
     html_options[:class] = class_names(
       html_options[:class],
       'button',
@@ -216,9 +245,10 @@ module ApplicationHelper
       html_options[:onclick] = "return confirm('\#{html_options[:onclick][:confirm]}');"
     end
 
-    if type == :link && !(html_options[:onclick] || html_options.dig(:data, :turbo_stream))
-      name += '...'
-    end
+    link_is_local = html_options[:onclick] || html_options.dig(:data, :turbo_stream)
+    name = name.to_s
+    name += '...' if type == :link && !link_is_local
+    name = svg_tag("pictograms/#{image}", name) if image
 
     [name, html_options]
   end

app/helpers/quantities_helper.rb

@@ -1,2 +1,11 @@
 module QuantitiesHelper
+  def quantities_check_boxes
+    # Closing <details> on focusout event depends on relatedTarget for internal
+    # actions being non-null. To ensure this, all top-layer elements of
+    # ::details-content must accept focus, e.g. <label> needs tabindex="-1" */
+    collection_check_boxes(nil, :quantity, @quantities, :id, :to_s_with_depth,
+                           include_hidden: false) do |b|
+      content_tag :li, b.label(tabindex: -1) { b.check_box + b.text }
+    end
+  end
 end

app/javascript/application.js

@@ -9,31 +9,70 @@ function showPage(event) {
 }
 document.addEventListener('turbo:load', showPage)
 
+function detailsChange(event) {
+  var target = event.currentTarget
+  var count = target.querySelectorAll('input:checked:not([disabled])').length
+  var span = target.querySelector('summary > span')
+  var button = target.querySelector('button')
+  if (count > 0) {
+    span.textContent = count + ' selected';
+    Turbo.StreamElement.prototype.enableElement(button)
+  } else {
+    span.textContent = span.getAttribute('data-prompt')
+    Turbo.StreamElement.prototype.disableElement(button)
+  }
+}
+window.detailsChange = detailsChange
+
+/* Close open <details> when focus lost */
+function detailsClose(event) {
+  if (!event.relatedTarget ||
+      event.relatedTarget.closest("details") != event.currentTarget) {
+    event.currentTarget.removeAttribute("open")
+  }
+}
+window.detailsClose = detailsClose
+
+window.detailsObserver = new MutationObserver((mutations) => {
+  mutations[0].target.dispatchEvent(new Event('change', {bubbles: true}))
+});
+
 
 /* Turbo stream actions */
+Turbo.StreamElement.prototype.disableElement = function(element) {
+    element.setAttribute("disabled", "disabled")
+    element.setAttribute("aria-disabled", "true")
+    element.setAttribute("tabindex", "-1")
+}
+Turbo.StreamActions.disable = function() {
+  this.targetElements.forEach((e) => { this.disableElement(e) })
+}
+
 Turbo.StreamElement.prototype.enableElement = function(element) {
     element.removeAttribute("disabled")
     element.removeAttribute("aria-disabled")
-    // 'tabindex' is not used explicitly, so removing it is safe
+    // Assume 'tabindex' is not used explicitly, so removing it is safe
     element.removeAttribute("tabindex")
 }
-
-Turbo.StreamActions.disable = function() {
-  this.targetElements.forEach((e) => {
-    e.setAttribute("disabled", "disabled")
-    e.setAttribute("aria-disabled", "true")
-    e.setAttribute("tabindex", "-1")
-  })
-}
-
 Turbo.StreamActions.enable = function() {
   this.targetElements.forEach((e) => { this.enableElement(e) })
 }
 
+/* TODO: change to visibility = collapse to avoid width change? */
 Turbo.StreamActions.hide = function() {
   this.targetElements.forEach((e) => { e.style.display = "none" })
 }
 
+Turbo.StreamActions.show = function() {
+  this.targetElements.forEach((e) => { e.style.removeProperty("display") })
+}
+
+/*
+Turbo.StreamActions.collapse = function() {
+  this.targetElements.forEach((e) => { e.style.visibility = "collapse" })
+}
+*/
+
 Turbo.StreamActions.close_form = function() {
   this.targetElements.forEach((e) => {
     /* Move focus if there's no focus or focus inside form being closed */
@@ -54,28 +93,63 @@ Turbo.StreamActions.close_form = function() {
   })
 }
 
+Turbo.StreamActions.unselect = function() {
+  this.targetElements.forEach((e) => {
+    e.checked = false
+    this.enableElement(e)
+  })
+}
+
+function formProcessKey(event) {
+  switch (event.key) {
+    case "Escape":
+      event.currentTarget.querySelector("a[name=cancel]").click()
+      break
+    case "Enter":
+      event.currentTarget.querySelector("button[name=button]").click()
+      event.preventDefault()
+      break
+  }
+}
+window.formProcessKey = formProcessKey
+
+function detailsProcessKey(event) {
+  // TODO: up/down arrows to move focus to prev/next line
+  switch (event.key) {
+    case "Escape":
+      if (event.currentTarget.hasAttribute("open")) {
+        event.currentTarget.removeAttribute("open")
+        event.stopPropagation()
+      }
+      break
+    case "Enter":
+      var button = event.currentTarget.querySelector("button:not([disabled])")
+      if (button) {
+        button.click()
+        // Autofocus won't be respected unless target is blurred
+        event.target.blur()
+        event.preventDefault()
+        event.stopPropagation()
+      }
+      break
+  }
+}
+window.detailsProcessKey = detailsProcessKey;
 
 /* Items table drag and drop support */
-function processKey(event) {
-  if (event.key == "Escape") {
-    event.currentTarget.querySelector("a[name=cancel]").click();
-  }
-}
-window.processKey = processKey;
-
-var lastEnterTime;
+var lastEnterTime
 function dragStart(event) {
-  lastEnterTime = event.timeStamp;
-  var row = event.currentTarget;
+  lastEnterTime = event.timeStamp
+  var row = event.currentTarget
   row.closest("table").querySelectorAll("thead tr").forEach((tr) => {
-    tr.toggleAttribute("hidden");
-  });
-  event.dataTransfer.setData("text/plain", row.getAttribute("data-drag-path"));
-  var rowRectangle = row.getBoundingClientRect();
-  event.dataTransfer.setDragImage(row, event.x - rowRectangle.left, event.y - rowRectangle.top);
-  event.dataTransfer.dropEffect = "move";
+    tr.toggleAttribute("hidden")
+  })
+  event.dataTransfer.setData("text/plain", row.getAttribute("data-drag-path"))
+  var rowRectangle = row.getBoundingClientRect()
+  event.dataTransfer.setDragImage(row, event.x - rowRectangle.left, event.y - rowRectangle.top)
+  event.dataTransfer.dropEffect = "move"
 }
-window.dragStart = dragStart;
+window.dragStart = dragStart
 
 /*
 * Drag tracking assumptions (based on FF 122.0 experience):
@@ -87,44 +161,44 @@ window.dragStart = dragStart;
 * and outside. This should probably be fixed in browser, than patched here.
 */
 function dragEnter(event) {
-  //console.log(event.timeStamp + " " + event.type + ": " + event.currentTarget.id);
-  dragLeave(event);
-  lastEnterTime = event.timeStamp;
-  const id = event.currentTarget.getAttribute("data-drop-id");
-  document.getElementById(id).classList.add("dropzone");
+  //console.log(event.timeStamp + " " + event.type + ": " + event.currentTarget.id)
+  dragLeave(event)
+  lastEnterTime = event.timeStamp
+  const id = event.currentTarget.getAttribute("data-drop-id")
+  document.getElementById(id).classList.add("dropzone")
 }
-window.dragEnter = dragEnter;
+window.dragEnter = dragEnter
 
 function dragOver(event) {
-  event.preventDefault();
+  event.preventDefault()
 }
-window.dragOver = dragOver;
+window.dragOver = dragOver
 
 function dragLeave(event) {
-  //console.log(event.timeStamp + " " + event.type + ": " + event.currentTarget.id);
+  //console.log(event.timeStamp + " " + event.type + ": " + event.currentTarget.id)
   // Leave has been accounted for by Enter at the same timestamp, processed earlier
-  if (event.timeStamp <= lastEnterTime) return;
+  if (event.timeStamp <= lastEnterTime) return
   event.currentTarget.closest("table").querySelectorAll(".dropzone").forEach((tr) => {
-    tr.classList.remove("dropzone");
-  });
+    tr.classList.remove("dropzone")
+  })
 }
-window.dragLeave = dragLeave;
+window.dragLeave = dragLeave
 
 function dragEnd(event) {
-  dragLeave(event);
+  dragLeave(event)
   event.currentTarget.closest("table").querySelectorAll("thead tr").forEach((tr) => {
-    tr.toggleAttribute("hidden");
-  });
+    tr.toggleAttribute("hidden")
+  })
 }
-window.dragEnd = dragEnd;
+window.dragEnd = dragEnd
 
 function drop(event) {
-  event.preventDefault();
+  event.preventDefault()
 
-  var params = new URLSearchParams();
-  var id_param = event.currentTarget.getAttribute("data-drop-id-param");
-  var id = event.currentTarget.getAttribute("data-drop-id").split("_").pop();
-  params.append(id_param, id);
+  var params = new URLSearchParams()
+  var id_param = event.currentTarget.getAttribute("data-drop-id-param")
+  var id = event.currentTarget.getAttribute("data-drop-id").split("_").pop()
+  params.append(id_param, id)
 
   fetch(event.dataTransfer.getData("text/plain"), {
     body: params,
@@ -138,4 +212,4 @@ function drop(event) {
   .then(response => response.text())
   .then(html => Turbo.renderStreamMessage(html))
 }
-window.drop = drop;
+window.drop = drop

app/models/quantity.rb

@@ -15,8 +15,8 @@ class Quantity < ApplicationRecord
     errors.add(:parent, :descendant_reference) if ancestor_of?(parent)
   end
   validates :name, presence: true, uniqueness: {scope: [:user_id, :parent_id]},
-    length: {maximum: type_for_attribute(:name).limit}
-  validates :description, length: {maximum: type_for_attribute(:description).limit}
+    length: {maximum: type_for_attribute(:name).limit || Float::INFINITY}
+  validates :description, length: {maximum: type_for_attribute(:description).limit || Float::INFINITY}
 
   # Update :depths of progenies after parent change
   before_save if: :parent_changed? do

app/models/setting.rb

@@ -0,0 +1,20 @@
+# Key-value store for runtime application settings that are configured through
+# the web setup wizard (or updated by an administrator) rather than hard-coded
+# in application.rb.
+#
+# Known keys:
+#   skip_email_confirmation  – "true"/"false", mirrors the homonymous option
+#                              that was previously in application.rb.
+class Setting < ApplicationRecord
+  validates :key, presence: true, uniqueness: true
+
+  # Return the string value stored for +key+, or +default+ when absent.
+  def self.get(key, default: nil)
+    find_by(key: key)&.value || default
+  end
+
+  # Persist +value+ for +key+, creating the record if it does not yet exist.
+  def self.set(key, value)
+    find_or_initialize_by(key: key).update!(value: value.to_s)
+  end
+end

app/models/unit.rb

@@ -3,7 +3,8 @@ class Unit < ApplicationRecord
 
   belongs_to :user, optional: true
   belongs_to :base, optional: true, class_name: "Unit"
-  has_many :subunits, class_name: "Unit", inverse_of: :base, dependent: :restrict_with_error
+  has_many :subunits, class_name: "Unit", inverse_of: :base,
+    dependent: :restrict_with_error
 
   validate if: ->{ base.present? } do
     errors.add(:base, :user_mismatch) unless user_id == base.user_id
@@ -11,8 +12,8 @@ class Unit < ApplicationRecord
     errors.add(:base, :multilevel_nesting) if base.base_id?
   end
   validates :symbol, presence: true, uniqueness: {scope: :user_id},
-    length: {maximum: type_for_attribute(:symbol).limit}
-  validates :description, length: {maximum: type_for_attribute(:description).limit}
+    length: {maximum: type_for_attribute(:symbol).limit || Float::INFINITY}
+  validates :description, length: {maximum: type_for_attribute(:description).limit || Float::INFINITY}
   validates :multiplier, numericality: {equal_to: 1}, unless: :base
   validates :multiplier, numericality: {greater_than: 0, precision: true, scale: true}, if: :base
 

app/models/user.rb

@@ -12,10 +12,10 @@ class User < ApplicationRecord
     disabled: 0,    # administratively disallowed to sign in
   }, default: :active, validate: true
 
-  has_many :readouts, dependent: :destroy
+  has_many :readouts, dependent: :delete_all
   accepts_nested_attributes_for :readouts
-  has_many :quantities, dependent: :destroy
-  has_many :units, dependent: :destroy
+  has_many :quantities, dependent: :delete_all
+  has_many :units, dependent: :delete_all
 
   validates :email, presence: true, uniqueness: true,
     length: {maximum: type_for_attribute(:email).limit}
@@ -29,4 +29,11 @@ class User < ApplicationRecord
   def at_least(status)
     User.statuses[self.status] >= User.statuses[status]
   end
+
+  # Returns true when this user is the only admin account in the system.
+  # Used to block actions that would leave the application without an admin
+  # (account deletion, status demotion).
+  def sole_admin?
+    admin? && !User.admin.where.not(id: id).exists?
+  end
 end

app/views/default/units/index.html.erb

@@ -1,16 +1,17 @@
-<div class="rightside buttongrid">
+<div class="rightside-area buttongrid">
   <% if current_user.at_least(:active) %>
     <%# TODO: implement Import all %>
     <%#= image_button_to t('.import_all'), 'download-multiple-outline',
       import_all_default_units_path, data: {turbo_stream: true} %>
   <% end %>
-  <%= image_link_to t('.back'), 'arrow-left-bold-outline', units_path, class: 'tools' %>
+  <%= image_link_to t('.back'), 'arrow-left-bold-outline', units_path,
+    class: 'tools-area' %>
 </div>
 
-<table class="main items">
+<table class="main-area items">
   <thead>
     <tr>
-      <th><%= User.human_attribute_name(:symbol).capitalize %></th>
+      <th><%= Unit.human_attribute_name(:symbol) %></th>
       <% if current_user.at_least(:active) %>
         <th><%= t '.actions' %></th>
       <% end %>

app/views/layouts/application.html.erb

@@ -47,7 +47,7 @@
       <%= render_flash_messages %>
     </div>
 
-    <%# Allow overwriting/clearing navigation menu for some views %>
+    <%# Allows overwriting/clearing navigation menu for some views %>
     <nav class="navigation">
       <%= content_for(:navigation) || (navigation_menu if user_signed_in?) %>
     </nav>

app/views/measurements/_form.html.erb

@@ -1,24 +1,36 @@
-<%= tabular_form_with model: Measurement.new do |form| %>
-  <fieldset>
+<%= tabular_form_with model: Measurement.new, id: :measurement_form,
+  class: 'topside-area vflex', html: {onkeydown: 'formProcessKey(event)'} do |form| %>
   <table class="items centered">
-      <tbody id="readouts">
-        <tr id="readouts_form">
-          <td colspan="4">
-            <%= collection_select :quantity, :id, @quantities, :id, :to_s_with_depth,
-              {prompt: t('.select_quantity'), disabled: '', selected: ''},
-              {name: :id, class: 'quantity vexpand',
-               onchange: "this.form.requestSubmit(new_readout_submit);"} %>
-            <%= form.submit id: :new_readout_submit, name: nil, value: nil,
-              formaction: new_readout_path, formmethod: :get, formnovalidate: true,
-              hidden: true, data: {turbo_stream: true} %>
-          </td>
-        </tr>
-      </tbody>
+    <tbody id="readouts"></tbody>
   </table>
-  </fieldset>
-  <div class="hflex centered">
-    <%= form.button -%>
+
+  <div class="hflex">
+    <%# TODO: right-click selection %>
+    <details id="quantity_select" class="hexpand" open
+             onkeydown="detailsProcessKey(event)">
+      <summary autofocus>
+        <!-- TODO: Set content with CSS when span empty to avoid duplication -->
+        <span data-prompt="<%= t('.select_quantity') %>">
+          <%= t('.select_quantity') %>
+        </span>
+        <%= image_button_tag t(:apply), "update", name: nil, disabled: true,
+          formaction: new_readout_path, formmethod: :get, formnovalidate: true,
+          data: {turbo_stream: true} %>
+      </summary>
+      <ul><%= quantities_check_boxes %></ul>
+    </details>
+    <%= form.button id: :create_measurement_button, disabled: true -%>
+  </div>
+
+  <div class="hflex reverse">
     <%= image_link_to t(:cancel), "close-outline", measurements_path, name: :cancel,
       class: 'dangerous', onclick: render_turbo_stream('form_close') %>
   </div>
 <% end %>
+
+<script>
+  quantity_select.addEventListener('focusout', detailsClose)
+  quantity_select.addEventListener('change', detailsChange)
+  detailsObserver.observe(quantity_select.querySelector('ul'),
+    {subtree: true, attributeFilter: ['disabled']})
+</script>

app/views/measurements/_form_close.html.erb

@@ -1,2 +1,4 @@
-<%= turbo_stream.update :measurement_form %>
 <%= turbo_stream.update :flashes %>
+<%= turbo_stream.remove :measurement_form %>
+<%= turbo_stream.show :no_items -%>
+<%= turbo_stream.enable :new_measurement_link -%>

app/views/measurements/index.html.erb

@@ -1,5 +1,5 @@
 <%# TODO: show hint when no quantities/units defined %>
-<div class="rightside buttongrid">
+<div class="rightside-area buttongrid">
   <% if current_user.at_least(:active) %>
     <%= image_link_to t('.new_measurement'), 'plus-outline', new_measurement_path,
       id: :new_measurement_link, onclick: 'this.blur();',
@@ -7,9 +7,7 @@
   <% end %>
 </div>
 
-<%= tag.div class: 'topside', id: :measurement_form %>
-
-<table class="main">
+<table class="main-area">
   <tbody id="measurements">
     <%= render(@measurements) || render_no_items %>
   </tbody>

app/views/measurements/new.turbo_stream.erb

@@ -1,4 +1,5 @@
 <%= turbo_stream.disable :new_measurement_link -%>
-<%= turbo_stream.update :measurement_form do %>
+<%= turbo_stream.hide :no_items -%>
+<%= turbo_stream.append_all 'body' do %>
   <%= render partial: 'form' %>
 <% end %>

app/views/quantities/_form.html.erb

@@ -1,5 +1,5 @@
 <%= tabular_fields_for @quantity, form: form_tag do |form| %>
-  <%- tag.tr id: row, class: "form", onkeydown: "processKey(event)",
+  <%- tag.tr id: row, class: "form", onkeydown: "formProcessKey(event)",
     data: {link: link, form: form_tag, hidden_row: hidden_row} do %>
 
     <td style="--depth:<%= @quantity.depth %>">

app/views/quantities/index.html.erb

@@ -1,20 +1,20 @@
-<div class="rightside buttongrid">
+<div class="rightside-area buttongrid">
   <% if current_user.at_least(:active) %>
     <%= image_link_to t('.new_quantity'), 'plus-outline', new_quantity_path,
       id: dom_id(Quantity, :new, :link), onclick: 'this.blur();',
       data: {turbo_stream: true} %>
   <% end %>
   <%#= image_link_to t('.import_quantities'), 'download-outline', default_quantities_path,
-    class: 'tools' %>
+    class: 'tools-area' %>
 </div>
 
-<%= tag.div class: 'main', id: :quantity_form %>
+<%= tag.div class: 'main-area', id: :quantity_form %>
 
-<table class="main items">
+<table class="main-area items">
   <thead>
     <tr>
-      <th><%= Quantity.human_attribute_name(:name).capitalize %></th>
-      <th><%= Quantity.human_attribute_name(:description).capitalize %></th>
+      <th><%= Quantity.human_attribute_name(:name) %></th>
+      <th><%= Quantity.human_attribute_name(:description) %></th>
       <% if current_user.at_least(:active) %>
         <th><%= t :actions %></th>
         <th></th>

app/views/readouts/_form.html.erb

@@ -1,22 +1,25 @@
 <%# TODO: add readout reordering by dragging %>
 <%= tabular_fields_for 'readouts[]', readout do |form| %>
-  <%- tag.tr id: dom_id(readout.quantity, :new, :readout),
-             onkeydown: 'processKey(event)' do %>
+  <%- tag.tr id: dom_id(readout.quantity, :new, :readout) do %>
+    <td class="actions">
+      <%# TODO: change to _link_ after giving up displaying relative paths %>
+      <%= image_button_tag '', 'delete-outline', class: 'dangerous', name: nil,
+        formaction: discard_readouts_path(readout.quantity),
+        formmethod: :get, formnovalidate: true, data: {turbo_stream: true} %>
+    </td>
     <td>
       <%= readout.quantity.relative_pathname(@superquantity) %>
     </td>
     <td>
-      <%= form.number_field :value, required: true, autofocus: true, size: 10 %>
+      <%= form.number_field :value, required: true,
+        size: readout.type_for_attribute(:value).precision / 2,
+        autofocus: readout_counter == 0 %>
     </td>
     <td>
       <%= form.hidden_field :quantity_id %>
       <%= form.collection_select :unit_id, @user_units, :id,
-        ->(u){ sanitize('&emsp;' * (u.base_id ? 1 : 0) + u.symbol) } %>
-    </td>
-    <td class="actions">
-      <%= image_button_tag '', 'delete-outline', class: 'dangerous', name: :discard,
-        formaction: discard_readouts_path(readout.quantity),
-        formmethod: :get, formnovalidate: true, data: {turbo_stream: true} %>
+        ->(u){ sanitize('&emsp;' * (u.base_id ? 1 : 0) + u.symbol) },
+        {prompt: t('.select_unit'), disabled: '', selected: ''}, required: true %>
     </td>
   <% end %>
 <% end %>

app/views/readouts/discard.turbo_stream.erb

@@ -1,4 +1,4 @@
+<%= turbo_stream.disable :create_measurement_button if @prev_quantities.one? %>
 <%= turbo_stream.remove dom_id(@quantity, :new, :readout) %>
-<%= turbo_stream.disable_all 'button[name="discard"]' if @prev_quantities.one? %>
-<%= turbo_stream.enable_all "select.quantity option[value='#{@quantity.id}']" %>
 <%= render partial: 'form_repath' %>
+<%= turbo_stream.unselect dom_id(@quantity) %>

app/views/readouts/new.turbo_stream.erb

@@ -1,9 +1,8 @@
-<%= render partial: 'form_repath' %>
-<%# is .one? proper condition? can @readouts be empty? %>
-<%= turbo_stream.enable_all 'button[name="discard"]' if @prev_quantities.one? %>
 <% @readouts.each do |r| %>
-  <%= turbo_stream.disable_all "select.quantity option[value='#{r.quantity_id}']" %>
+  <%= turbo_stream.disable dom_id(r.quantity) %>
 <% end %>
-<%= turbo_stream.before :readouts_form do %>
+<%= render partial: 'form_repath' %>
+<%= turbo_stream.append :readouts do %>
   <%= render partial: 'form', collection: @readouts, as: :readout %>
 <% end %>
+<%= turbo_stream.enable :create_measurement_button if @prev_quantities.empty? %>

app/views/setup/new.html.erb

@@ -0,0 +1,39 @@
+<%= form_with url: setup_path, method: :post, class: "labeled-form main-area" do %>
+
+  <h3 style="grid-column: 1 / -1; text-align: left; margin: 0;">
+    <%= t(".admin_account") %>
+  </h3>
+
+  <label for="admin_email"><%= t(".admin_email") %></label>
+  <%= email_field_tag :admin_email, params[:admin_email],
+        id: "admin_email", required: true, size: 30, autofocus: true,
+        autocomplete: "email" %>
+
+  <label for="admin_password"><%= t(".admin_password") %></label>
+  <%= password_field_tag :admin_password, nil,
+        id: "admin_password", required: true, size: 30,
+        autocomplete: "new-password" %>
+
+  <label for="admin_password_confirmation"><%= t(".admin_password_confirmation") %></label>
+  <%= password_field_tag :admin_password_confirmation, nil,
+        id: "admin_password_confirmation", required: true, size: 30,
+        autocomplete: "off" %>
+
+  <h3 style="grid-column: 1 / -1; text-align: left; margin: 0.5em 0 0 0;">
+    <%= t(".options") %>
+  </h3>
+
+  <label for="skip_email_confirmation" style="grid-column: 1 / 3; text-align: left;">
+    <%= check_box_tag :skip_email_confirmation, "1",
+          params[:skip_email_confirmation] == "1",
+          id: "skip_email_confirmation" %>
+    <%= t(".skip_email_confirmation") %>
+  </label>
+
+  <label for="seed_units" style="grid-column: 1 / 3; text-align: left;">
+    <%= check_box_tag :seed_units, "1", true, id: "seed_units" %>
+    <%= t(".seed_units") %>
+  </label>
+
+  <%= submit_tag t(".submit") %>
+<% end %>

app/views/units/_form.html.erb

@@ -1,5 +1,5 @@
 <%= tabular_fields_for @unit, form: form_tag do |form| %>
-  <%- tag.tr id: row, class: "form", onkeydown: "processKey(event)",
+  <%- tag.tr id: row, class: "form", onkeydown: "formProcessKey(event)",
     data: {link: link, form: form_tag, hidden_row: hidden_row} do %>
 
     <td style="--depth:<%= @unit.base_id? ? 1 : 0 %>">

app/views/units/index.html.erb

@@ -1,19 +1,20 @@
-<div class="rightside buttongrid">
+<div class="rightside-area buttongrid">
   <% if current_user.at_least(:active) %>
     <%= image_link_to t('.new_unit'), 'plus-outline', new_unit_path,
       id: dom_id(Unit, :new, :link), onclick: 'this.blur();', data: {turbo_stream: true} %>
   <% end %>
-  <%= image_link_to t('.import_units'), 'download-outline', default_units_path, class: 'tools' %>
+  <%= image_link_to t('.import_units'), 'download-outline', default_units_path,
+    class: 'tools-area' %>
 </div>
 
 <%= tag.div id: :unit_form %>
 
-<table class="main items">
+<table class="main-area items">
   <thead>
     <tr>
-      <th><%= User.human_attribute_name(:symbol).capitalize %></th>
-      <th><%= User.human_attribute_name(:description).capitalize %></th>
-      <th><%= User.human_attribute_name(:multiplier).capitalize %></th>
+      <th><%= Unit.human_attribute_name(:symbol) %></th>
+      <th><%= Unit.human_attribute_name(:description) %></th>
+      <th><%= Unit.human_attribute_name(:multiplier) %></th>
       <% if current_user.at_least(:active) %>
         <th><%= t :actions %></th>
         <th></th>

app/views/users/confirmations/new.html.erb

@@ -1,8 +1,9 @@
-<div class="main">
-  <%= labelled_form_for resource, url: user_confirmation_path do |f| %>
-    <%= f.email_field :email, required: true, size: 30, autofocus: true, autocomplete: "email",
-      value: (resource.pending_reconfirmation? ? resource.unconfirmed_email : resource.email) %>
+<%= labeled_form_for resource, url: user_confirmation_path,
+  html: {class: 'main-area'} do |f| %>
+
+  <%= f.email_field :email, required: true, size: 30, autofocus: true,
+    autocomplete: 'email', value:
+    resource.pending_reconfirmation? ? resource.unconfirmed_email : resource.email %>
 
   <%= f.submit t(:resend_confirmation) %>
 <% end %>
-</div>

app/views/users/index.html.erb

@@ -1,12 +1,10 @@
-<table class="main items" id="users">
+<table class="main-area items" id="users">
   <thead>
     <tr>
-      <th><%= User.human_attribute_name(:email).capitalize %></th>
-      <th><%= User.human_attribute_name(:status).capitalize %></th>
-      <th><%= User.human_attribute_name(:confirmed_at).capitalize %></th>
-      <th>
-        <%= User.human_attribute_name(:created_at).capitalize %>&nbsp;<sup>UTC</sup>
-      </th>
+      <th><%= User.human_attribute_name(:email) %></th>
+      <th><%= User.human_attribute_name(:status) %></th>
+      <th><%= User.human_attribute_name(:confirmed_at) %></th>
+      <th><%= User.human_attribute_name(:created_at) %>&nbsp;<sup>(UTC)</sup></th>
       <th><%= t :actions %></th>
     </tr>
   </thead>
@@ -19,18 +17,18 @@
             <%= user.status %>
           <% else %>
             <%= form_for user do |u| %>
-              <%= u.select :status, User.statuses.keys, {}, autocomplete: "off",
-                onchange: "this.form.requestSubmit();" %>
+              <%= u.select :status, User.statuses.keys, {}, autocomplete: 'off',
+                onchange: 'this.form.requestSubmit();' %>
             <% end %>
           <% end %>
         </td>
         <td class="svg">
-          <%= svg_tag "pictograms/checkbox-marked-outline" if user.confirmed_at.present? %>
+          <%= svg_tag 'pictograms/checkbox-marked-outline' if user.confirmed_at.present? %>
         </td>
-        <td><%= user.created_at.to_fs(:db_without_sec) %></td>
+        <td><%= l user.created_at, format: :without_tz %></td>
         <td class="actions">
           <% if allow_disguise?(user) %>
-            <%= image_link_to t(".disguise"), "incognito", disguise_user_path(user) %>
+            <%= image_link_to t('.disguise'), 'incognito', disguise_user_path(user) %>
           <% end %>
         </td>
       </tr>

app/views/users/mailer/confirmation_instructions.html.erb

@@ -1,5 +1,5 @@
 <p>Welcome <%= @email %>!</p>
 
 <p>You can confirm your account email through the link below:</p>
-
+<!-- FIXME: is confirmation_url valid route prefix? -->
 <p><%= link_to 'Confirm my account', confirmation_url(@resource, confirmation_token: @token) %></p>

app/views/users/passwords/edit.html.erb

@@ -1,13 +1,12 @@
-<div class="main">
-  <%= labelled_form_for resource, url: user_password_path, html: {method: :put} do |f| %>
-    <%= f.hidden_field :reset_password_token, label: false %>
+<%= labeled_form_for resource, url: user_password_path,
+  html: {method: :put, class: 'main-area'} do |f| %>
 
-    <%= f.password_field :password, label: t(".new_password"), required: true, size: 30,
-      minlength: @minimum_password_length, autofocus: true, autocomplete: "new-password",
-      hint: t("users.minimum_password_length", count: @minimum_password_length) %>
-    <%= f.password_field :password_confirmation, label: t(".password_confirmation"),
-      required: true, size: 30, minlength: @minimum_password_length, autocomplete: "off" %>
+  <%= f.hidden_field :reset_password_token %>
 
-    <%= f.submit t(".update_password") %>
+  <%= f.password_field :password, required: true, size: 30, autofocus: true,
+    minlength: @minimum_password_length, autocomplete: 'new-password' %>
+  <%= f.password_field :password_confirmation, required: true, size: 30,
+    minlength: @minimum_password_length, autocomplete: 'off' %>
+
+  <%= f.submit t('.update_password') %>
 <% end %>
-</div>

app/views/users/passwords/new.html.erb

@@ -1,7 +1,8 @@
-<div class="main">
-  <%= labelled_form_for resource, url: user_password_path do |f| %>
-    <%= f.email_field :email, required: true, size: 30, autofocus: true, autocomplete: "email" %>
+<%= labeled_form_for resource, url: user_password_path,
+  html: {class: 'main-area'} do |f| %>
+
+  <%= f.email_field :email, required: true, size: 30, autofocus: true,
+    autocomplete: 'email' %>
 
   <%= f.submit t(:recover_password) %>
 <% end %>
-</div>

app/views/users/registrations/edit.html.erb

@@ -1,31 +1,29 @@
 <% content_for :navigation, flush: true do %>
-  <%= link_to svg_tag("pictograms/arrow-left-bold-outline", t(:back)),
+  <%= link_to svg_tag('pictograms/arrow-left-bold-outline', t(:back)),
     request.referer.present? ? :back : root_path, class: 'tab' %>
 <% end %>
 
-<div class="rightside buttongrid">
-  <%= image_button_to t(".delete"), "account-remove-outline", user_registration_path,
-    form_class: 'tools', method: :delete, data: {turbo: false},
-    onclick: {confirm: t(".confirm_delete")} %>
+<div class="rightside-area buttongrid">
+  <%= image_button_to_if !current_user.sole_admin?, t('.delete'), 'account-remove-outline',
+    user_registration_path, form_class: 'tools-area', method: :delete, data: {turbo: false},
+    onclick: {confirm: t('.confirm_delete')} %>
 </div>
 
-<%= labelled_form_for resource, url: registration_path(resource),
-                      html: {method: :patch, class: 'main'} do |f| %>
-  <%= f.email_field :email, size: 30, autofocus: true, autocomplete: "off" %>
-  <% if f.object.pending_reconfirmation? %>
-    <%= f.text_field :unconfirmed_email, readonly: true, tabindex: -1,
-      hint: t(".unconfirmed_email_hint",
-              timestamp: f.object.confirmation_sent_at.to_fs(:db_without_sec)) %>
+<%= labeled_form_for resource, url: registration_path(resource),
+  html: {method: :patch, class: 'main-area'} do |f| %>
+
+  <%= f.email_field :email, size: 30, autofocus: true, autocomplete: 'off' %>
+  <% if resource.pending_reconfirmation? %>
+    <%= f.text_field :unconfirmed_email, readonly: true,
+      confirmation_sent_at: l(resource.confirmation_sent_at) %>
   <% end %>
 
   <%= f.select :status, User.statuses, readonly: true %>
 
-  <%= f.password_field :password, label: t(".new_password"), size: 30,
-    minlength: @minimum_password_length, autocomplete: "new-password",
-    hint: t(".blank_password_hint_html",
-            subhint: t("users.minimum_password_length", count: @minimum_password_length)) %>
-  <%= f.password_field :password_confirmation, label: t(".password_confirmation"),
-    size: 30, minlength: @minimum_password_length, autocomplete: "off" %>
+  <%= f.password_field :password, size: 30, autocomplete: 'new-password',
+    minlength: @minimum_password_length %>
+  <%= f.password_field :password_confirmation, size: 30, autocomplete: 'off',
+    minlength: @minimum_password_length %>
 
-  <%= f.submit t(".update") %>
+  <%= f.submit %>
 <% end %>

app/views/users/registrations/new.html.erb

@@ -1,16 +1,16 @@
-<div class="main">
-  <%= labelled_form_for resource, url: user_registration_path do |f| %>
-    <%= f.email_field :email, required: true, size: 30, autofocus: true, autocomplete: "email" %>
+<div class="main-area">
+  <%= labeled_form_for resource, url: user_registration_path do |f| %>
+    <%= f.email_field :email, required: true, size: 30, autofocus: true,
+      autocomplete: 'email' %>
     <%= f.password_field :password, required: true, size: 30,
-      minlength: @minimum_password_length, autocomplete: "new-password",
-      hint: t("users.minimum_password_length", count: @minimum_password_length) %>
-    <%= f.password_field :password_confirmation, label: t(".password_confirmation"),
-      required: true, size: 30, minlength: @minimum_password_length, autocomplete: "off" %>
+      minlength: @minimum_password_length, autocomplete: 'new-password' %>
+    <%= f.password_field :password_confirmation, required: true, size: 30,
+      minlength: @minimum_password_length, autocomplete: 'off' %>
 
     <%= f.submit t(:register) %>
   <% end %>
 
-  <%= content_tag :p, t(:or), style: "text-align: center;" %>
-  <%= image_link_to t(:resend_confirmation), "email-sync-outline", new_user_confirmation_path,
-    class: "centered" %>
+  <%= content_tag :p, t(:or), style: 'text-align: center;' %>
+  <%= image_link_to t(:resend_confirmation), 'email-sync-outline',
+    new_user_confirmation_path, class: 'centered' %>
 </div>

app/views/users/sessions/new.html.erb

@@ -1,17 +1,18 @@
-<div class="main">
-  <%= labelled_form_for resource, url: user_session_path do |f| %>
-    <%= f.email_field :email, required: true, size: 30, autofocus: true, autocomplete: "email" %>
-    <%= f.password_field :password, required: true, size: 30, minlength: @minimum_password_length,
-      autocomplete: "current-password" %>
+<div class="main-area">
+  <%= labeled_form_for resource, url: user_session_path do |f| %>
+    <%= f.email_field :email, required: true, size: 30, autofocus: true,
+      autocomplete: 'email' %>
+    <%= f.password_field :password, required: true, size: 30,
+      minlength: @minimum_password_length, autocomplete: 'current-password' %>
 
     <% if devise_mapping.rememberable? %>
-      <%= f.check_box :remember_me, label: t(".remember_me") %>
+      <%= f.check_box :remember_me %>
     <% end %>
 
     <%= f.submit t(:sign_in) %>
   <% end %>
 
-  <%= content_tag :p, t(:or), style: "text-align: center;" %>
+  <%= content_tag :p, t(:or), style: 'text-align: center;' %>
   <%= image_link_to t(:recover_password), 'lock-reset', new_user_password_path,
     class: 'centered' %>
 </div>

app/views/users/show.html.erb

@@ -1,19 +1,18 @@
 <% content_for :navigation, flush: true do %>
-  <div class="left">
-    <%= image_link_to t(:back), "arrow-left-bold-outline", users_path %>
-  </div>
+  <%= link_to svg_tag('pictograms/arrow-left-bold-outline', t(:back)), users_path,
+    class: 'tab' %>
 <% end %>
 
-<%= labelled_form_for @user do |f| %>
+<%= labeled_form_for @user, html: {class: 'main-area'} do |f| %>
   <%= f.email_field :email, readonly: true %>
-  <% if f.object.pending_reconfirmation? %>
+  <% if @user.pending_reconfirmation? %>
     <%= f.email_field :unconfirmed_email, readonly: true,
-      hint: t("users.registrations.edit.unconfirmed_email_hint",
-              timestamp: f.object.confirmation_sent_at.to_fs(:db_without_sec)) %>
+      confirmation_sent_at: l(@user.confirmation_sent_at) %>
   <% end %>
 
+  <%# TODO: allow status change here? %>
   <%= f.select :status, User.statuses, readonly: true %>
 
   <%= f.text_field :created_at, readonly: true %>
-  <%= f.text_field :confirmed_at, readonly: true %>
+  <%= f.text_field :confirmed_at, readonly: true, placeholder: t(:no) %>
 <% end %>

config/application.rb.dist

@@ -54,5 +54,9 @@ module FixinMe
 
     # Sender address of account registration-related messages
     Devise.mailer_sender = 'noreply@localhost'
+
+    # Whether to skip e-mail confirmation for new registrations is configured
+    # through the web setup wizard and stored in the database (Setting model),
+    # so it does not need to be set here.
   end
 end

config/initializers/time_formats.rb

@@ -1,3 +0,0 @@
-# Format contains non-breaking space:
-#   160.chr(Encoding::UTF_8)
-Time::DATE_FORMATS[:db_without_sec] = "%Y-%m-%d %H:%M"

config/initializers/turbo_streams_tag_builder.rb

@@ -19,7 +19,19 @@ ActiveSupport.on_load :turbo_streams_tag_builder do
     action :hide, target, allow_inferred_rendering: false
   end
 
+  def show(target)
+    action :show, target, allow_inferred_rendering: false
+  end
+
+  #def collapse(target)
+  #  action :collapse, target, allow_inferred_rendering: false
+  #end
+
   def close_form(target)
     action :close_form, target, allow_inferred_rendering: false
   end
+
+  def unselect(target)
+    action :unselect, target, allow_inferred_rendering: false
+  end
 end

config/locales/en.yml

@@ -1,22 +1,28 @@
 en:
+  time:
+    formats:
+      # Format contains non-breaking space: 160.chr(Encoding::UTF_8)
+      default: "%Y-%m-%d %H:%M %Z"
+      without_tz: "%Y-%m-%d %H:%M"
   errors:
     messages:
       precision_exceeded: must not exceed %{value} significant digits
       scale_exceeded: must not exceed %{value} decimal digits
   activerecord:
     attributes:
-      unit:
-        symbol: Symbol
+      quantity:
+        description: Description
         name: Name
-        multiplier: Multiplier
+      unit:
         base: Base unit
+        description: Description
+        multiplier: Multiplier
+        symbol: Symbol
       user:
-        email: e-mail
-        status: status
-        password: password
-        created_at: registered
-        confirmed_at: confirmed
-        unconfirmed_email: Awaiting confirmation for
+        confirmed_at: Confirmed
+        created_at: Registered
+        email: E-mail
+        status: Status
     errors:
       models:
         unit:
@@ -53,9 +59,22 @@ en:
           The request is semantically incorrect and was rejected (422 Unprocessable Entity).
           This should not happen, please notify site administrator.
   helpers:
+    label:
+      user:
+        password_confirmation: 'Retype new password:'
+        password_length_hint_html:
+          count: '%{minimum_password_length}'
+          zero:
+          one: <br><em>(%{count} character minimum)</em>
+          other: <br><em>(%{count} characters minimum)</em>
+        remember_me: 'Remember me:'
+        unconfirmed_email_html: >
+          Awaiting confirmation for:<br><em>(since %{confirmation_sent_at})</em>
     submit:
       create: Create
       update: Update
+      user:
+        update: Update profile
   layouts:
     application:
       issue_tracker: Report issue
@@ -66,12 +85,12 @@ en:
     navigation: Measurements
     no_items: There are no measurements taken. You can Add some now.
     form:
-      select_quantity: select the measured quantity...
+      select_quantity: select the measured quantities...
     index:
       new_measurement: Add measurement
   readouts:
     form:
-      new_children: Children
+      select_unit: ...
   quantities:
     navigation: Quantities
     no_items: There are no configured quantities. You can Add some or Import from defaults.
@@ -129,33 +148,47 @@ en:
       disguise: View as
     passwords:
       edit:
-        new_password: New password
-        password_confirmation: Retype new password
+        password_html: 'New password:%{password_length_hint_html}'
         update_password: Update password
     registrations:
       new:
-        password_confirmation: Retype password
+        password_html: 'Password:%{password_length_hint_html}'
+        password_confirmation: 'Retype password:'
       edit:
         confirm_delete: Are you sure you want to delete profile?
           All data will be irretrievably lost.
         delete: Delete profile
-        unconfirmed_email_hint: (since %{timestamp})
-        new_password: New password
-        password_confirmation: Retype new password
-        blank_password_hint_html: leave blank to keep unchanged<br>%{subhint}
-        update: Update profile
-    sessions:
-      new:
-        remember_me: Remember me
-    minimum_password_length:
-      zero:
-      one: (%{count} character minimum)
-      other: (%{count} characters minimum)
+        password_html: >
+          New password:
+          <br><em>leave blank to keep unchanged</em>
+          %{password_length_hint_html}
+  registrations:
+    destroy:
+      sole_admin: You cannot delete the only admin account.
   actions: Actions
+  setup:
+    new:
+      admin_account: Admin account
+      admin_email: 'E-mail:'
+      admin_password: 'Password:'
+      admin_password_confirmation: 'Retype password:'
+      options: Options
+      skip_email_confirmation: Skip e-mail confirmation for new registrations
+      seed_units: Seed built-in default units
+      submit: Set up
+    create:
+      email_blank: E-mail cannot be blank.
+      password_blank: Password cannot be blank.
+      password_mismatch: Passwords do not match.
+      success: >
+        Installation complete. You can now sign in with the admin account you
+        just created.
   add: Add
+  apply: Apply
   back: Back
   cancel: Cancel
   delete: Delete
+  :no: 'no'
   or: or
   register: Register
   sign_in: Sign in

config/routes.rb

@@ -1,4 +1,7 @@
 Rails.application.routes.draw do
+  # Web-based installation wizard — only reachable when no admin exists yet.
+  resource :setup, only: [:new, :create], controller: :setup
+
   resources :measurements
 
   resources :readouts, only: [:new] do

db/migrate/20230602185352_create_units.rb

@@ -5,7 +5,7 @@ class CreateUnits < ActiveRecord::Migration[7.0]
       t.string :symbol, null: false, limit: 15
       t.text :description
       t.decimal :multiplier, null: false, precision: 30, scale: 15, default: 1.0
-      t.references :base, foreign_key: {to_table: :units}
+      t.references :base, foreign_key: {to_table: :units, on_delete: :cascade}
 
       t.timestamps null: false
     end

db/migrate/20250104194343_create_quantities.rb

@@ -4,7 +4,7 @@ class CreateQuantities < ActiveRecord::Migration[7.2]
       t.references :user, foreign_key: true
       t.string :name, null: false, limit: 31
       t.text :description
-      t.references :parent, foreign_key: {to_table: :quantities}
+      t.references :parent, foreign_key: {to_table: :quantities, on_delete: :cascade}
 
       t.timestamps null: false
 

db/migrate/20260228171524_create_settings.rb

@@ -0,0 +1,12 @@
+class CreateSettings < ActiveRecord::Migration[7.2]
+  def change
+    create_table :settings do |t|
+      t.string :key, null: false
+      t.string :value
+
+      t.timestamps
+    end
+
+    add_index :settings, :key, unique: true
+  end
+end

db/schema.rb

@@ -69,11 +69,11 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
     t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
-  add_foreign_key "quantities", "quantities", column: "parent_id"
+  add_foreign_key "quantities", "quantities", column: "parent_id", on_delete: :cascade
   add_foreign_key "quantities", "users"
   add_foreign_key "readouts", "quantities"
   add_foreign_key "readouts", "units"
   add_foreign_key "readouts", "users"
-  add_foreign_key "units", "units", column: "base_id"
+  add_foreign_key "units", "units", column: "base_id", on_delete: :cascade
   add_foreign_key "units", "users"
 end

db/seeds.rb

@@ -3,6 +3,17 @@
 #   bin/rails db:seed
 # command (or created alongside the database with db:setup).
 # Seeding process should be idempotent.
+#
+# Admin account setup
+# -------------------
+# The preferred way to create the first admin account is through the web setup
+# wizard, which is shown automatically on the first visit when no admin exists.
+# The wizard also lets you configure runtime options (e.g. skip e-mail
+# confirmation) and seed the default units without using the command line.
+#
+# The block below provides an alternative CLI path for headless / automated
+# deployments.  It is skipped when an admin account already exists (e.g. after
+# the web wizard has run).
 
 User.transaction do
   break if User.find_by status: :admin

db/seeds/templates/units.erb

@@ -1,5 +1,5 @@
 Unit.transaction do
-  Unit.defaults.order(Unit.arel_table[:base_id].eq(nil)).delete_all
+  Unit.defaults.delete_all
   units = {}
 <% Unit.defaults.ordered.each do |unit| %>
 <%= "\n" if unit.base.nil? %>

db/seeds/units.rb

@@ -1,5 +1,5 @@
 Unit.transaction do
-  Unit.defaults.order(Unit.arel_table[:base_id].eq(nil)).delete_all
+  Unit.defaults.delete_all
 
   units = {}
 

test/application_system_test_case.rb

@@ -1,7 +1,6 @@
 require "test_helper"
 
 class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
-  extend ActionView::Helpers::TranslationHelper
   include ActionView::Helpers::UrlHelper
 
   # NOTE: geckodriver installed with Firefox, ignore incompatibility warning
@@ -19,8 +18,8 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
 
   def sign_in(user: users.select(&:confirmed?).sample, password: randomize_user_password!(user))
     visit new_user_session_url
-    fill_in User.human_attribute_name(:email).capitalize, with: user.email
-    fill_in User.human_attribute_name(:password).capitalize, with: password
+    fill_in User.human_attribute_name(:email), with: user.email
+    fill_in User.human_attribute_name(:password), with: password
     click_on t(:sign_in)
     user
   end
@@ -30,6 +29,13 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
     evaluate_script("arguments[0].insertAdjacentHTML('beforeend', '#{button.html_safe}');", after)
   end
 
+  # Allow skipping interpolations when translating for testing purposes
+  INTERPOLATION_PATTERNS = Regexp.union(I18n.config.interpolation_patterns)
+  def translate(key, **options)
+    options.empty? ? super.split(INTERPOLATION_PATTERNS, 2).first : super
+  end
+  alias :t :translate
+
   #def assert_stale(element)
   #  assert_raises(Selenium::WebDriver::Error::StaleElementReferenceError) { element.tag_name }
   #end

test/controllers/registrations_controller_test.rb

@@ -0,0 +1,18 @@
+require "test_helper"
+
+class RegistrationsControllerTest < ActionDispatch::IntegrationTest
+  test "sole admin cannot delete account" do
+    sign_in users(:admin)
+    delete user_registration_path
+    assert_redirected_to edit_user_registration_path
+    assert_equal t("registrations.destroy.sole_admin"), flash[:alert]
+    assert User.exists?(users(:admin).id)
+  end
+
+  test "non-admin can delete account" do
+    sign_in users(:alice)
+    assert_difference ->{ User.count }, -1 do
+      delete user_registration_path
+    end
+  end
+end

test/system/units_test.rb

@@ -6,14 +6,14 @@ require "application_system_test_case"
 #  * user with no units
 
 class UnitsTest < ApplicationSystemTestCase
-  LINK_LABELS = {
-    new_unit: t('units.index.new_unit'),
-    new_subunit: t('units.unit.new_subunit'),
-    edit: nil
-  }
+  LINK_LABELS = {}
 
   setup do
     @user = sign_in
+
+    LINK_LABELS.clear
+    LINK_LABELS[:new_unit] = t('units.index.new_unit')
+    LINK_LABELS[:new_subunit] = t('units.unit.new_subunit')
     LINK_LABELS[:edit] = Regexp.union(@user.units.map(&:symbol))
 
     visit units_path
@@ -26,7 +26,7 @@ class UnitsTest < ApplicationSystemTestCase
     end
 
     # Cannot #destroy_all due to {dependent: :restrict*} on Unit.subunits association
-    @user.units.order(Unit.arel_table[:base_id].eq(nil)).delete_all
+    @user.units.delete_all
     visit units_path
     within 'tbody' do
       assert_selector 'tr', count: 1

test/system/users_test.rb

@@ -6,15 +6,21 @@ class UsersTest < ApplicationSystemTestCase
   end
 
   test "sign in" do
+    visit new_user_session_path
+    assert find_link(href: new_user_session_path)[:disabled]
+
     sign_in
     assert_no_current_path new_user_session_path
-    assert_text t("devise.sessions.signed_in")
+    assert_text t('devise.sessions.signed_in')
   end
 
-  test "sign in fails with invalid password" do
+  test 'sign in fails with invalid password' do
     sign_in password: random_password
     assert_current_path new_user_session_path
-    assert_text t("devise.failure.invalid", authentication_keys: User.human_attribute_name(:email))
+    assert_text t('devise.failure.not_found_in_database',
+                  authentication_keys: User.human_attribute_name(:email))
+    assert find_link(href: new_user_session_path)[:disabled]
+    assert_not_empty find_field(User.human_attribute_name(:email)).value
   end
 
   test "sign out" do
@@ -29,7 +35,7 @@ class UsersTest < ApplicationSystemTestCase
     visit new_user_session_url
     click_on t(:recover_password)
 
-    fill_in User.human_attribute_name(:email).capitalize,
+    fill_in User.human_attribute_name(:email),
       with: users.select(&:confirmed?).sample.email
     assert_emails 1 do
       click_on t(:recover_password)
@@ -42,8 +48,8 @@ class UsersTest < ApplicationSystemTestCase
       visit Capybara.string(mail.body.to_s).find_link("Change my password")[:href]
     end
     new_password = random_password
-    fill_in t("users.passwords.edit.new_password"), with: new_password
-    fill_in t("users.passwords.edit.password_confirmation"), with: new_password
+    fill_in t("users.passwords.edit.password_html"), with: new_password
+    fill_in t("helpers.label.user.password_confirmation"), with: new_password
     assert_emails 1 do
       click_on t("users.passwords.edit.update_password")
       # Wait until redirected to make sure async request has been processed
@@ -56,9 +62,9 @@ class UsersTest < ApplicationSystemTestCase
     visit new_user_session_url
     click_on t(:register)
 
-    fill_in User.human_attribute_name(:email).capitalize, with: random_email
+    fill_in User.human_attribute_name(:email), with: random_email
     password = random_password
-    fill_in User.human_attribute_name(:password).capitalize, with: password
+    fill_in User.human_attribute_name(:password), with: password
     fill_in t("users.registrations.new.password_confirmation"), with: password
     assert_difference ->{User.count}, 1 do
       assert_emails 1 do
@@ -82,7 +88,7 @@ class UsersTest < ApplicationSystemTestCase
     click_on t(:register)
     click_on t(:resend_confirmation)
 
-    fill_in User.human_attribute_name(:email).capitalize,
+    fill_in User.human_attribute_name(:email),
       with: users.reject(&:confirmed?).sample.email
     assert_emails 1 do
       click_on t(:resend_confirmation)
@@ -143,7 +149,7 @@ class UsersTest < ApplicationSystemTestCase
   end
 
   test "delete profile" do
-    user = sign_in
+    user = sign_in user: users.reject(&:admin?).select(&:confirmed?).sample
     # TODO: remove condition after root_url changed to different path than
     # profile in routes.rb
     unless has_current_path?(edit_user_registration_path)
@@ -151,9 +157,18 @@ class UsersTest < ApplicationSystemTestCase
     end
     assert_difference ->{ User.count }, -1 do
       accept_confirm { click_on t("users.registrations.edit.delete") }
-    end
       assert_current_path new_user_session_path
     end
+    assert_text t("devise.registrations.destroyed")
+  end
+
+  test "sole admin cannot delete profile" do
+    sign_in user: users(:admin)
+    unless has_current_path?(edit_user_registration_path)
+      first(:link_or_button, users(:admin).email).click
+    end
+    assert find(:button, t("users.registrations.edit.delete"))[:disabled]
+  end
 
   test "index forbidden for non admin" do
     sign_in user: users.reject(&:admin?).select(&:confirmed?).sample