Small change to standard themes (Obsidian, Ridgeline, Tidal)
The December 10, 2025 release of ArcGIS StoryMaps added a new SHAPE property to StoryMap themes that enables you to configure the rounding of corners for media blocks and other visual elements in your ArcGIS StoryMaps content.
The new styles (from left to right) are called sharp, soft, and curved. You can see a video showing how these look in this blog: What's new in ArcGIS StoryMaps (December 2025).
This SHAPE property has been applied to the standard themes in a way that reflects the previous styling of the buttons in each theme. This helps to realize our original vision for the standard themes.
This means that media blocks and other elements now have curved corners in any content that uses Obsidian and soft corners when using Ridgeline and Tidal.
Summit, Mesa, and Slate continue to have sharp corners.
If you wish to go back to using the original Obsidian, you can find it in the featured themes gallery. Simply apply the "Obsidian (original)" theme, then republish your content. Of course you can also use the original version on any new ArcGIS StoryMap items you create, if you prefer the original.