Document night mode
Invert the drawing to a dark sheet for low-light viewing.
Document night mode renders the PDF on a dark field and remaps colors so the drawing is comfortable to read in low light — without changing the underlying document.
Toggle it from the status bar or with its keyboard shortcut. Night mode affects only how the page is displayed; exported files keep their original colors.
App theme vs. document night mode
The app's light/dark theme (set in Preferences) controls the editor chrome. Document night mode controls only the drawing sheet. They're independent.
A related hairlines only option forces imported vector lines to render at 1px, which can make dense drawings easier to read.