Appearance
Creating Themes
Themes customize Bike's colors, materials, and typography. A theme is a single .bktheme file that you can write yourself, adapt from an existing theme, and share with others. For choosing and installing finished themes, see Using Themes.
I built theming because the way an outline looks really matters when you stare at it all day. With a theme you control the typeface and sizing, the text and background colors, the materials Bike draws with, and the small details that make an outline feel like yours. The easiest way to start is to open a theme you already like, copy it, and change one thing at a time until it feels right.
One detail worth knowing before you dig in: Bike lets you pick a separate theme for light mode and dark mode in Settings > Appearance. So you don't have to make a single theme that works in both. You can design one theme tuned for daylight and another for night, and Bike will switch between them with the system.
When you're ready to write or modify a .bktheme file, the full reference lives in the extension-kit docs: