anchor.diff:  image::apim/3.x/installation/portal-ui/portal-url.png[]
   ====
   
  -==== Top menu
  +=== Top menu
   FULLSCREEN:: This button opens the preview in a new window, making it easier to edit if you have several screens.
   NOTE: This button is only visible if you configure a Portal URL, as described above.
   
  
positive.code: :page-keywords: Gravitee.io, API Platform, API Management, API Gateway, oauth2, openid, documentation, manual, guide, reference, api
  :page-layout: apim3x
  
  == Mandatory configuration
  The only mandatory value in the `config.json` file is:
  
  [source,json]
  ----
  {
    "baseURL": "gravitee_portal_api_url"
  }
  ----
  
  It describes where the APIM API Portal endpoint is, and must be set so APIM Portal can send requests to it.
  
  == Default configuration
  
  [source,json]
  ----
  include::https://raw.githubusercontent.com/gravitee-io/gravitee-portal-webui/master/src/assets/config.json[]
  ----
  
  == Configure the APIM Portal theme
  You can change the default theme of APIM Portal to your own custom theme.
  
  === Using APIM Console
  
  You customize the theme in APIM Console with the *Settings > Theme* menu option.
  
  image::apim/3.x/installation/portal-ui/graviteeio-portal-configuration-theme.png[]
  
  Whenever you change a setting, you can see the change reflected in the live preview on the right.
  
  [NOTE]
  ====
  
negative.code: 
  Fonts:: Choose your font family and sizes. Medium sizes are used by default.
  
  === Advanced customization
  
  If you want to customize further, you can define the graphic properties to expose for each component.
  
  Each component uses its own properties, but where possible, we group the properties into common variables such as the ones listed in <<Basic customization>> above.
  
  You can see common component colors, for example, by holding your mouse over the color bubble.
  For other property types, if a common property is used, you can see this in the placeholder field.
  
  == Override theme files
  APIM API comes with a default theme and two default logos:
  
  * `definition.json`
  * `logo.png`
  * `logo-light.png`
  
  These files are located in the `/themes` folder of the API distribution folder.
  
  To customize the Portal theme you can either modify these three files or specify a new folder in the `gravitee.yml` file:
  
  