First you'll need to place selected themes in your `themes` directory (i.e `~/.config/helix/themes`), the directory might have to be created beforehand.
To use a custom theme add `theme = <name>` to your [`config.toml`](./configuration.md) or override it during runtime using `:theme <name>`.
The default theme.toml can be found [here](https://github.com/helix-editor/helix/blob/master/theme.toml), and user submitted themes [here](https://github.com/helix-editor/helix/blob/master/runtime/themes).
First create a file with the name of your theme as file name (i.e `mytheme.toml`) and place it in your `themes` directory (i.e `~/.config/helix/themes`).
Each line in the theme file is specified as below:
where `key` represents what you want to style, `fg` specifies the foreground color, `bg` the background color, and `modifiers` is a list of style modifiers. `bg` and `modifiers` can be omitted to defer to the defaults.
To specify only the foreground color:
```toml
key = "#ffffff"
```
if the key contains a dot `'.'`, it must be quoted to prevent it being parsed as a [dotted key](https://toml.io/en/v1.0.0#keys).
```toml
"key.key" = "#ffffff"
```
Possible modifiers:
| Modifier |
| --- |
| `bold` |
| `dim` |
| `italic` |
| `underlined` |
| `slow\_blink` |
| `rapid\_blink` |
| `reversed` |
| `hidden` |
| `crossed\_out` |
Possible keys:
| Key | Notes |
| --- | --- |
| `attribute` | |
| `keyword` | |
| `keyword.directive` | Preprocessor directives (\#if in C) |
| `namespace` | |
| `punctuation` | |
| `punctuation.delimiter` | |
| `operator` | |
| `special` | |
| `property` | |
| `variable` | |
| `variable.parameter` | |
| `type` | |
| `type.builtin` | |
| `constructor` | |
| `function` | |
| `function.macro` | |
| `function.builtin` | |
| `comment` | |
| `variable.builtin` | |
| `constant` | |
| `constant.builtin` | |
| `string` | |
| `number` | |
| `escape` | Escaped characters |
| `label` | For lifetimes |
| `module` | |
| `ui.background` | |
| `ui.linenr` | |
| `ui.statusline` | |
| `ui.popup` | |
| `ui.window` | |
| `ui.help` | |
| `ui.text` | |
| `ui.text.focus` | |
| `ui.menu.selected` | |
| `ui.selection` | For selections in the editing area |
| `warning` | LSP warning |
| `error` | LSP error |
| `info` | LSP info |
| `hint` | LSP hint |
These keys match [tree-sitter scopes](https://tree-sitter.github.io/tree-sitter/syntax-highlighting#theme). We half-follow the common scopes from [macromates language grammars](https://macromates.com/manual/en/language_grammars) with some differences.
For a given highlight produced, styling will be determined based on the longest matching theme key. So it's enough to provide function to highlight `function.macro` and `function.builtin` as well, but you can use more specific scopes to highlight specific cases differently.
