JetBrains / IntelliJ terminal renders Codex CLI user-vs-assistant distinction too weak compared to Ghostty/iTerm

What feature would you like to see?

I want the Codex CLI UI to remain readable in JetBrains terminal emulators (IntelliJ IDEA and related JetBrains IDEs).

Today, the visual distinction between user input and Codex output is much weaker in JetBrains embedded terminals than it is in Ghostty or iTerm.

Current behavior

In JetBrains terminal:

• the separation between my prompts and Codex responses is hard to scan
• the left-margin markers are too subtle
• the color / contrast hierarchy is weak enough that long sessions visually blur together

In comparison, the same Codex CLI session is much easier to read in:

• Ghostty
• iTerm

What I would expect

Even if the terminal host differs, Codex should still present enough hierarchy that users can immediately distinguish:

• user prompt blocks
• assistant response blocks
• tool / progress lines

Suggested improvements

Any of these would help:

1. Stronger default contrast between user and assistant blocks
2. More distinct markers / separators in the left margin
3. Optional high-contrast TUI mode for terminals with weaker rendering
4. Detect JetBrains terminal environments and increase contrast / separation automatically

Why this matters

When scrolling through a long session in JetBrains terminal, it is much harder to tell who is speaking than in Ghostty or iTerm. The result is that Codex feels visually muddled even though the exact same CLI output is clear in other terminals.

Environment

• Codex CLI version: 0.114.0
• Terminal where it looks bad: JetBrains embedded terminal (IntelliJ IDEA / JetBrains IDEs)
• Terminals where it looks good: Ghostty, iTerm
• Platform: macOS

Additional context

There is already a broader issue about improving visual distinction between user input and AI output, but this report is specifically about the JetBrains embedded terminal experience being noticeably worse than Ghostty/iTerm for the same Codex CLI UI.