Some icons are not suitable for dark themes (very low contrast- Hardly visible)

[raindropsfromsky]

The Box button

Toolbar in the Pyflow dialog:

The text in the Rec button is too tiny to be readable (I have set the button size to be 28x28 px).
Instead of putting text, it is better to have just the red circle, which is universally recognized as "record" function.

Desired:
The buttons should have high contrast to be easily visible.