Engineering Ledger — a theme for Redmine 6

A refined, technical-editorial theme for Redmine 6.x. Ink-dark chrome over a warm paper canvas, petrol and rust accents, and IBM Plex Sans + Mono for the data-dense screens Redmine is full of.

Highlights

• Dark "engineering" header and main menu with a rust signature hairline
• Warm paper content canvas with crisp white cards and soft shadows
• Monospace (IBM Plex Mono) for IDs, dates, durations and other tabular data
• Petrol interaction colour, rust for identity/emphasis, tuned status palettes
• Reworked forms, buttons, tables, journals, flash messages, login and the query Options panel
• Responsive-aware: respects Redmine's own mobile breakpoints (no desktop-only overrides leaking into the hamburger layout)

Requirements

• Redmine 6.0+ (uses the Rails asset pipeline; themes live under app/assets/themes/)
• Outbound access to Google Fonts, or self-host IBM Plex and adjust the @import at the top of stylesheets/application.css (see Offline / self-hosted fonts)

Installation

The theme must be installed into a directory named engineering-ledger — Redmine derives the body class (theme-Engineering-ledger) from the directory name, and every selector in this theme is scoped to that class.

cd /path/to/redmine

# Clone into the correctly-named theme directory
git clone https://github.com/io7/redmine-engineering-ledger.git \
  app/assets/themes/engineering-ledger

# Compile the theme into public/assets
RAILS_ENV=production bin/rails assets:precompile

# Restart your Redmine app server (systemd unit name will vary)
sudo systemctl restart redmine-puma

Then enable it: Administration → Settings → Display → Theme → "Engineering-ledger" → Save.

Installing by downloading the ZIP instead of cloning? Unpack it and rename the extracted folder to engineering-ledger before placing it in app/assets/themes/.

Updating

cd /path/to/redmine/app/assets/themes/engineering-ledger
git pull
cd /path/to/redmine
RAILS_ENV=production bin/rails assets:precompile
sudo systemctl restart redmine-puma

Customisation

The palette and radii are CSS custom properties declared in :root at the top of stylesheets/application.css. Override what you like — e.g. swap the accent:

:root {
  --accent:   #15727d;  /* petrol — interaction        */
  --warm:     #c2581f;  /* rust   — identity / emphasis */
  --paper:    #f4f1ea;  /* canvas                       */
  --radius:   5px;
}

After editing, re-run assets:precompile and restart.

Offline / self-hosted fonts

Line 2 of stylesheets/application.css pulls IBM Plex from Google Fonts. To run without external requests, download IBM Plex Sans + Mono, drop the @font-face declarations into this file (or a sibling), and remove the Google Fonts @import. The theme falls back to the system sans/mono stack if the fonts are unavailable.

Uninstall

Set the theme back to the default in Administration → Settings → Display, then:

rm -rf /path/to/redmine/app/assets/themes/engineering-ledger
RAILS_ENV=production bin/rails assets:precompile
sudo systemctl restart redmine-puma

How it works

Redmine loads a theme by letting its stylesheets/application.css shadow the core application.css in the layout's stylesheet tag. That is why line 1 re-imports the core stylesheet:

@import url(../../../stylesheets/application.css);

Everything after it is an override layered on top of stock Redmine, scoped to body.theme-Engineering-ledger. This is the same mechanism the bundled fluentmine theme uses.

License

MIT — see LICENSE.

Redmine is © Jean-Philippe Lang, distributed under the GNU GPL v2. This theme is an independent stylesheet that extends Redmine's base CSS at runtime; it bundles no Redmine source.