Themes

applanch ships with three built-in themes and supports fully custom theme palettes.

Built-in Themes

Theme	Description
Follow system	Automatically switches between Light and Dark based on the Windows setting
Light	Light background, dark text
Dark	Dark background (navy), light text

Switch themes in Settings under Appearance → Theme.

Custom Themes

Built-in themes are loaded from Config/theme-palette.json. Add your own themes under Config/UserDefined/theme-palette/*.json.

For the full JSON field reference, see Theme JSON Format.

Adding a Custom Theme

1. Create a JSON file under Config/UserDefined/theme-palette/ (for example my-theme.json).
2. Define your custom themes in that file.
3. Restart applanch.

{
  "themes": [
    {
      "id": "my-theme",
      "displayNames": {
        "en": "My Theme",
        "ja": "マイテーマ"
      },
      "entries": [
        { "key": "Brush.AppBackground", "hex": "#1E1E2E" },
        { "key": "Brush.Surface",       "hex": "#27273A" }
      ]
    }
  ]
}

The file is merged with built-in themes, so you only need to define what you want to add or override.

Referencing Another Theme

Instead of specifying entries directly, set entriesFrom to inherit all brush values from an existing theme:

• Use a string value when one theme should always inherit from the same source theme.
• Use an object with light and dark when the source theme should change with the Windows light/dark mode.
• The referenced theme ID can be either a built-in theme such as light / dark, or a custom theme ID that you defined in another JSON file.

This is useful when you want to add an alias theme or reuse an existing palette without repeating the full entries list.

Always inherit from a single theme:

{
  "id": "my-light-copy",
  "displayNames": { "en": "My Light Copy" },
  "entriesFrom": "light"
}

Switch the inherited theme based on the Windows color mode:

{
  "id": "my-dark-variant",
  "displayNames": { "en": "Dark Variant" },
  "entriesFrom": {
    "light": "light",
    "dark": "dark"
  }
}

When the Windows setting is light, the light source theme ID is used; when dark, the dark source theme ID is used. This is how the built-in Follow system theme works.