set-cursor-line-bg

name: set-cursor-line-bg description: Use when adjusting the cursor line highlight color or opacity for a theme in linux-lit — changes how prominently the current line is highlighted argument-hint: | darker | lighter

Set Cursor Line Background

Sets the linux-lit.cursor_line_bg field in ~/utono/themes/.config/themes/themes-unified.json for a specific theme. This controls the highlight color of the current line in the reader.

cursor_line_bg drives BOTH the static current-line highlight AND the fade-out animation that plays on the previously-current line when the cursor moves. The fade interpolates alpha down to 0 over its hue (see src/input/highlight.rs, which reads cursor_line_bg via theme::rgba_str_to_rgb). So changing this one field updates the highlight and its fade together — there is no separate "fade color" field. (Historically the fade wrongly used the window root_color, so it read as the theme's blue regardless of this setting; that's fixed.)

Format

The value is an RGBA CSS string: rgba(R, G, B, alpha) where alpha controls intensity.

Typical alpha range for readability:

• 0.15 — very subtle
• 0.25 — moderate
• 0.30 — visible (current rose-pine-dawn default)
• 0.40 — strong

Steps

1. Parse the argument for theme name and desired change
2. Read themes-unified.json, find the theme object
3. If the theme has no linux-lit section, create one
4. If the user gave a specific RGBA value, use it directly
5. If the user said "darker" or "lighter", read the current value (or derive from dwl.focuscolor) and adjust alpha by +0.05 or -0.05
6. If no color is specified, derive from dwl.focuscolor with the requested alpha
7. Write the cursor_line_bg field
8. Run cargo build to verify
9. Report the change — user will restart linux-lit to see the result

Location

The theme JSON is at:

~/utono/themes/.config/themes/themes-unified.json

The field lives under the theme's linux-lit key:

{
  "rose-pine-dawn": {
    "linux-lit": {
      "cursor_line_bg": "rgba(196, 120, 138, 0.30)"
    }
  }
}

Rust fallback

If no linux-lit.cursor_line_bg exists, src/theme.rs derives one from dwl.focuscolor at alpha 0.13 (light) or 0.15 (dark). Adding the JSON field overrides this.