How to reproduce:
1. Create a new Unity project
2. In the Project window, right-click -> Create -> Shader Graph -> Any Shader Graph
3. Open the created Shader Graph
4. In the Shader Graph Blackboard, click "+" -> Category
5. Observe the color of text of the Category header 

Expected result: The text color is suitable and has enough contrast 
Actual results: The text is poorly visible

Reproducible with: 6000.0.56f1, 6000.1.16f1, 6000.2.1f1, 6000.3.0a5

Reproducible on: Ubuntu 24, macOS Sequoia 15.5 (M1)
Not reproducible on: No other environment tested