mulmoterminal-theme

Make a colour scheme of your own

themes in ~/.mulmoterminal/config.json defines schemes that appear in Settings' picker next to the four built-ins, and that a project can then name in its .mulmoterminal.json theme key. Settings can choose a theme; nothing in the app can create one. This skill is that path.

This is the whole app's palette — panel backgrounds, borders, accent, text. A single project's badge and header colours are a different thing (mulmoterminal-dirs).

How to run this

1. Find out what they're going after

Ask for the direction first, with concrete options rather than "what colours?":

• From something that exists — a painting, a photo, a brand, an editor theme they like. This is the easiest to do well: take 5–8 colours off the source and assign them to roles.
• A variant of a built-in — "Nord but warmer", "Daylight with more contrast". Use extends and write only the keys that differ.
• Light or dark, if it isn't already obvious. It decides every value below.

2. Decide extends — and know what it costs

{ "id": "arles", "label": "Van Gogh (Arles)", "extends": "daylight", "colors": { "--accent": "#c8971e" } }

• With extends, colors is a diff over that built-in (midnight / nord / daylight / solarized). Anything you leave out is inherited. Start here — it is far easier to get right, and a three-key diff is a real theme.
• Without extends, the theme must set every one of the 20 keys below. This is enforced when the config is saved, not when the theme is painted: an incomplete theme with no base is rejected outright rather than half-applied, because the missing half would inherit whatever the previous theme left on the element.

3. Write the colours

Assign the source's colours to roles, then say what each one is doing before you write it. Rules that matter more than taste:

• --text on --bg-base and --bg-panel must stay readable. Check the WCAG contrast ratio: gamma-decode each channel (c/255, then c<=0.03928 ? c/12.92 : ((c+0.055)/1.055)^2.4), weight 0.2126 R + 0.7152 G + 0.0722 B, ratio (lighter+0.05)/(darker+0.05). Aim for 4.5:1 or better for --text, and don't let --text-muted fall below 3:1 — a beautiful palette that can't be read is the usual way this goes wrong.
• --on-accent goes on --accent-bg, not on the page. Check it against that, and nothing else.
• A painting's colours are rarely usable raw. Backgrounds want the muted, desaturated end of the source; the accent wants its most saturated note. Taking six vivid colours and putting them in six roles produces something unusable at 12px.