Use Adf Skin to chane the Defaults

If you want to make changes to the appearance of Oracle Fusion Applications pages, like Change the Font size and Color any other Skin related changes. Use ADF Skin Editor to create a custom skin based on the Oracle Fusion Applications Skin Extension (fusionFx-simple) and apply that skin to your Oracle Fusion applications.

Created a Sample Application with UIShell (To Create UI Shell please fallow this post).

To create new ADFskins:

An ADF skin is a type of CSS file where you define CSS style properties based on the Cascading Style Sheet (CSS) specification for the component for which you want to customize the appearance.

1. In the Application Navigator, Right-click the ViewController project and select New from the context menu.

2. In the New Gallery, expand the Web Tier node, select JSF/Facelets and in the right hand pane, select ADF Skin as the item.

3. In the Create ADF Skin File dialog, change the file name to MyNewSkin.css. Append \MyNewSkin to the existing skins directory path. Check the Use as the default skin family for this project checkbox.

4. Please Select the Default Skin and click finish.

It will create a .CSS file in the location, it will update the "trinidad-config" file with Default Skin and it will update the "trinidad-skins" file with selected skin details.

Open the newly create css file. It will open in the ADF Skin Extension editor.

Select the "Selectors" View.

In the Selectors view, expand "Global Selectors Aliases" -> Font -> select AFDefaultFont:alias.

In the property inspector change the Font - size.

This will change all the font sizes in the application except Field level data(Content).

To change the Field level content, Expand "Faces Component Selectors" -> Expand the component "Input Text" -> Expand pseudo-Elements -> Select Content. Then open the property inspector and change the font-size.