If I choose white on black or others,I must undo many times to return default theme.That is inconvenient
Thanks. We provide the theme color just let our users to print it good to a paper.
@dillon
Oh.....I was thought that to make the editor more good-looking~
still. you need a way to revert to the default theme.
@Spongman we will make this better
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Brand new interactions and interfaces.
Smooth support for design sizes of over 3W
devices or 10W pads.
More rigorous design constraints, more
standardized processes
For enterprises, more professional users.
Easy to use and quick to get started.
The process supports design scales of 300
devices or 1000 pads.
Supports simple circuit simulation.
For students, teachers, creators.
Brand new interactions and interfaces. 
Easy to use and quick to get started. 
Thanks. We provide the theme color just let our users to print it good to a paper.