I have a lot of fancy CSS to make a focused workspace, but sometimes I like to switch to a look thats basically like notepad.exe
This is the toggle button https://chrome.google.com/webstore/detail/decreased-productivity/nlbpiflhmdcklcbihngeffpmoklbiooj
In it’s settings, you can paste your alternative custom CSS. Also, you can set it to maximum mode, where it strips away a lot of the default CSS too. I managed to tweak it to the point that it looks pretty identical to working in notepad.exe, but with all the controls of dynalist. I toggle between the modes via the extension icon.