The four themes
The picker shows a display name, the configuration file uses a shorter id. Both refer to the same theme.
There are exactly four, and none of them follows your terminal’s light or dark setting: you pick a theme explicitly. If you move between a bright room and a dark one, switching is one command.
Switch a theme in a session
In the picker,
↑/↓ (or k/j) previews a theme live, so the whole interface repaints as you move down the list. Enter accepts the highlighted theme and Esc reverts to what you had, which makes trying one out free.
The same control is in Settings. Press F2 (or run /settings), open Appearance and expand the Theme row to reach Appearance › Theme. The selected theme carries a filled marker and the label current. In that submenu ↑/↓/j/k navigate, Enter selects, ← goes back up to Appearance, d resets the theme to the default, and F2 or Esc closes Settings.
Whichever theme you pick, one rule does not move:
Themes never change the accent rule: banner green on focus only. The accent marks the focused selection and nothing else, so a theme changes the palette without changing what the interface is telling you.Set a theme in configuration
Set it once inconfig.toml and every new session starts with it:
/reload-config picks up a change made on disk without restarting the session. Configuration covers where the file lives and how project and personal settings combine.
Other display settings
Two more keys live next to the theme and change how much the interface moves and how loudly it speaks:/compact toggles a denser layout inside a session, which pairs well with a small terminal. For anything that is not the full interface, --color auto|always|never controls whether colour is emitted at all; use --color never when you are piping output into a file or a log. See Headless and scripting for the rest of the non-interactive options.
The default palette
These are the values the default theme uses. They are handy if you want your terminal profile, prompt or editor to sit next to the interface without clashing.
Three rules explain why the palette looks the way it does:
- The accent is the dominant background pixel of the Cortex banner, RGB
(31, 73, 69), which is#1F4945. - The accent never outlines a box. Borders are grey, so a focused panel is legible without a coloured frame competing with the content.
- Focused green glyphs get a near-white backing rather than disappearing on black, and descriptions next to them stay dim.
When colour looks wrong
A theme can only work with what the terminal gives it. If colours look flat or text is hard to read after switching:- Check that your terminal advertises true colour. A 256-colour profile approximates the palette, so the accent and the dim greys move closer together.
- Try Cortex Day if you run a light terminal background. A dark theme on a light background is the usual cause of unreadable dim text.
- Press
don the Theme row in Settings to go back to the default, or run/theme dark. - For output that is not the interface, remember that colour codes travel:
--color neveror a plain pipe destination gives you clean text. CLI troubleshooting covers mangled output in more detail.
Custom themes
A plugin can supply a theme: the plugin capability list includes themes, and a plugin can register a hook that overrides theme values. That is the supported extension point today, and it is described on CLI plugins.Pick one of the four built-ins, or ship a plugin that supplies a theme. Overriding individual palette roles by hand is not part of the documented surface for this build.