Theming lets you present AtoM as your institution's own service while keeping the underlying data model untouched. AtoM's front end is a Symfony application, and its look is delivered through theme plugins built on templates, CSS and a small amount of JavaScript. The discipline is to override, not to edit core - so your customisations survive upgrades.

Good customisation is also an accessibility exercise. Aim to meet WCAG 2.1 AA (contrast, keyboard operability, alt text) because a public archive serves the widest possible audience, and many jurisdictions require it of public bodies.

How themes are structured

A theme is a plugin under the plugins directory containing templates, module overrides and compiled assets. AtoM ships with the arDominionB5Plugin (Bootstrap 5) as the default modern theme.

  • Copy an existing theme to a new plugin name rather than modifying the shipped one.
  • Override only the templates you need; AtoM falls back to core for everything else.
  • Enable your theme under Admin > Plugins, then clear the cache.

Branding & assets

Replace the logo, banner and colour variables, and add your favicon. Because the theme is Bootstrap-based, most restyling is variable and CSS work rather than markup surgery.

  • Keep custom CSS in the theme so it is version-controlled and portable.
  • Rebuild and clear the cache after asset changes so the compiled front end updates.
In practice. Track your theme plugin in its own Git repository. When you upgrade AtoM, you redeploy the same theme against the new core and only reconcile templates that actually changed upstream - turning a risky re-skin into a routine merge.

Key takeaways

  • Override in a copied theme plugin; never edit core templates.
  • Restyle through Bootstrap variables and CSS, and target WCAG 2.1 AA.
  • Version-control the theme so upgrades stay a controlled merge.

Check your understanding

Last modified: Saturday, 1 August 2026, 11:03 AM