Arabic/Hebrew/Persian/Urdu chat text rendered left-to-right and
left-aligned, and mixed RTL/English technical messages (the common case)
read backwards. Resolve each chat block's base direction from its own
first strong character (UAX#9) with pure CSS, scoped to the chat
surfaces only:
- `unicode-bidi: plaintext` + `text-align: start` on assistant prose
blocks (p, h1-h6, li, blockquote), the user bubble's text lines, and
both composers (main + edit share the composer-rich-input slot). RTL
blocks read and right-align RTL; English stays LTR; mixed
conversations resolve per block. `text-align: start` is required
because the user bubble hardcodes `text-left`.
- Inline `code` and KaTeX are pinned `direction: ltr; unicode-bidi:
isolate`, so the bidi first-strong heuristic skips them: a sentence
that *starts* with a command (`./run.sh ...`) followed by Arabic
still resolves RTL, and the command's own neutrals keep their order.
- Fenced code surfaces (code-card, user fences) are pinned LTR so they
never mirror or right-align inside an RTL list item or blockquote.
`direction` is never forced, so app chrome, layout, and list indent
stay LTR per the issue's request not to flip the whole UI. English-only
content is byte-for-byte unchanged.
Salvaged and unified from #44065 and #44169; verified in Chromium that
isolate removes inline code from the paragraph direction vote (the
code-first case), making the JS dir-resolution in #44065 unnecessary.
Fixes#44150
Co-authored-by: Adolanium <Adolanium@users.noreply.github.com>
Co-authored-by: Adalsteinn Helgason <AIalliAI@users.noreply.github.com>
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