[BUG/FEATURE] Light Mode doesn't work in Zellij

[not-reed]

Description

when using https://zellij.dev/ opencode is always in dark mode. This alone could be a bug in how zellij reports system theme or something, however it would be nice to be able to manually select light/dark mode instead of only the 'theme' and have light-dark auto detected. 'system' seems to not actually follow the system in this case (only opencode has this issue for me)

OpenCode version

1.0.57

Steps to reproduce

1. install zellij
2. set light mode in zellij (catppuccin-latte)
3. start zellij (its light mode)
4. start opencode (its dark mode)

Screenshot and/or share link

No response

Operating System

Arch

Terminal

Ghostty 1.2.3

[rekram1-node]

will fix

[benodiwal]

@rekram1-node can i work on this issue ?

[linuxmobile]

@rekram1-node can i work on this issue ?

Light mode is working fine in zellij, the issue with zellij is the cache zellij-org/zellij#3590 (comment)

[pureboys]

upgrade zellij 0.43.1 is work for me

[smeijer]

Same issue inside Jetbrains IDE's. Does anyone know a fix?

[Br1an67]

I'd like to work on this. Added a theme_mode option (light / dark / system) to tui.json that overrides terminal background color detection — set "theme_mode": "light" to force light mode in Zellij or other terminals that misreport the system theme.

PR: #15612

[JuliaKalder]

Research Summary

Root Cause

The issue is caused by a Zellij cache bug (zellij-org/zellij#3590): OSC 10/11 queries return incorrect colors (always black) due to a caching problem. This causes opencode to incorrectly detect dark mode.

Terminal Detection Flow

1. opencode queries terminal background via
2. Zellij returns black due to cache bug
3. opencode detects dark background → applies dark mode

Affected Modules

• • Theme detection
• • Config validation

Proposed Solution (PR #15612)

Add config option to :

Valid values: , , (default)

Priority Order

1. (manual override) - highest
2. • persisted preference
3. Terminal detection (default)

Alternative Fix

Upgrade Zellij to 0.43.1+ which fixes the underlying cache issue.

Risks

• Low: Backward compatible (optional config)
• Works for JetBrains IDE terminals which have similar issues

Full research: logs/issues/4464/research.md