Coats and appearance

Choose a companion coat, set app appearance and create readable custom themes.

Mellow's companion coat and interface appearance help you recognize your agent and make the workspace comfortable to use. Start with a coat, then choose Light, Dark or System appearance. Advanced themes provide finer control over surfaces, typography and chat styling.

These settings apply to the Mellow app. The Visca website keeps its own visual identity, and documentation screenshots show the appearance captured in the app.

Choose your companion's coat

Open Settings → Coats & appearance. The coat gallery identifies the active agent and offers Lilac, Mint, Peach, Cloud, Cocoa and Midnight. Select a companion to apply its coat through Mellow's saved appearance selection.

The chosen coat affects the active agent and coordinated palette. When comparing agents, check which one is active before changing its coat. A custom avatar can differ from the built-in companion selection.

Built-in themes

Use Light for bright surfaces, Dark for dim surfaces, or System to follow the Mac's appearance. Appearance mode and a custom theme are separate choices; changing the appearance mode can clear an active custom theme so the selected mode can take effect.

Choose the look while viewing a real conversation with code, links and tool results. A pleasing empty screen is not enough to judge reading contrast.

Making your own theme

Use the theme library's create, edit or duplicate controls when a coat preset is not enough. Save edits to a built-in theme as a copy so you can return to the original.

Change one group at a time and preview a populated screen. Keep a known-good theme available while editing.

Give an agent its own theme

Open the agent's appearance settings under Your agents and select a visual theme when you want a distinct workspace for that agent. A default or unassigned choice lets the app's usual appearance apply.

For example, use a restrained dark palette for a coding agent and a brighter one for a writing agent. The color is an orientation aid; it does not change the agent's instructions, model or permissions.

Sharing themes

Export and import files

Export a theme from its menu to save a portable file. On another installation, import that file through the theme library. Imports receive their own local identity rather than replacing a built-in theme.

Review imported colors and embedded image backgrounds before adopting them. A theme can be technically valid yet difficult to read at your display brightness or text size.

Share a link

The app includes theme-sharing and link-import flows. They require a reachable sharing service. If publishing or resolving a link fails, use file export/import rather than assuming the theme has already been uploaded.

Do not treat a local save as publication. Wait for the sharing result and verify the destination before passing a link to someone else.

Troubleshooting

The theme management controls include library health, preview-cache cleanup, rollback and built-in-theme recovery. Use the narrowest action matching the problem.

File format

Advanced themes use JSON sections for metadata, colors, background, glass, typography, animation, shadows and optional message/border styling. Export a complete working theme as the editing baseline instead of assembling an incomplete object from a short example.

Retain the exported field names and color encoding. Edit values, re-import, and inspect validation before applying the result. Metadata and identity handling differ between an imported copy and an installed built-in theme; do not use identifiers to overwrite the built-in collection manually.

A comfortable final check

After saving, inspect a chat, settings, a selected control, a disabled control, a warning and a code block. Try a narrower window. If you use System mode, check both light and dark behavior. Keep motion restrained and preserve visible keyboard focus.