Open Settings → Appearance. You can change:
- the theme (light or dark), the editor font, and the text size,
- readable line width or full width,
- live preview, which hides Markdown symbols as you write,
- line numbers beside the note, which are on by default. You can also run "Toggle line numbers" from the command palette.
Which settings follow me?
When you're signed in, the theme, font, text size, width, live preview, and line numbers sync to your other devices, on the web and in the desktop app. Vim mode, hotkeys, and the formatting bar stay per device, because they usually depend on the keyboard you're using.