Is there any method to change the original theme of Web AppBuilder? Currently it only provides two themes, several colors and 2 layout for each theme. What if I want more options? Do I have to use the JavaScript to change that? Thanks!
Jake,
Here is the ESRI documentation to help you get started.
Create a theme—Web AppBuilder for ArcGIS (Developer Edition) | ArcGIS for Developers
To change a theme you mostly dive into json and css files. It all really depends on what you are after.
-Stan