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Advanced Theme Options

This section of “_data/theme.yml” configures advanced options such as image and font size, and Bootstrap themes. This is an optional section—-your site will work just fine without adjusting these variables, but they’re available if you’d like the extra options for customization.

CDM image % for IIIF:

CDM-Users only: This is a CONTENTdm-specific variable section for adjusting size of images used throughout the site. CollectionBuilder uses the IIIF Image API to retrieve images using a percentage size option. The percentage must be 10% or greater.


  • Default 70
    image-percentage-large: 50


  • Default 40
    image-percentage-medium: 30


  • Default 20
    image-percentage-small: 10

Pro Tip: If your images are appearing blurry or take too long to load, try adjusting the image-sizing settings. The appropriate percentage depends on the full size of images contained in your CDM repository and may require some experimentation.

These options will adjust the basic colors of your site’s navigation bar (see Bootstrap navbar docs for details).

  • Choose from navbar-light for use with light background colors, or navbar-dark for dark background colors.
    • Options: navbar-light, navbar-dark
      navbar-color: navbar-dark
  • Choose from Bootstrap’s background colors.
    • Options: bg-primary, bg-secondary, bg-success, bg-danger, bg-warning, bg-info, bg-light, bg-dark, bg-white, bg-dark
      navbar-background: bg-dark


Bootswatch creates unique themes for Bootstrap-based sites. Swap out the default Bootstrap for a Bootswatch version using the options below as a fun way to demonstrate the power of CSS to transform look and feel.


  • Leave blank or comment out (make a comment by placing a # in front of the variable) for plain bootstrap
    • Options: cerulean, cosmo, cyborg, darkly, flatly, journal, litera, lumen, lux, materia, minty, pulse, sandstone, simplex, sketchy, slate, solar, spacelab, superhero, united, yeti
      bootswatch: cerulean

Theme Fonts:

These options change the way the fonts appear throughout your collection. If you leave any option blank, it will revert to the CollectionBuilder defaults.


  • Changes the base size for fonts throughout the site.
    base-font-size: 1.2em


  • Changes the color of the base font. Probably want a shade of black …
    text-color: "#191919"
  • Changes the link color used throughout the site. Base color is a primary blue.
    link-color: "#17a2b8"


  • Changes the font family
    • If it’s a google family, you’ll need to use the font-cdn option below to add the style sheet link to the site.
      base-font-family: Georgia; serif;


  • This lets you add fonts from Google Fonts or other online resources provided by a content delivery network (cdn). These are typically provided by the service you are using.
    font-cdn: <link href="" rel="stylesheet">