ADR-007: Caption bidi strategy (<bdi> isolation + tatweel joiner)

• Status: accepted · Date: 2026-10-15

Context

Arabic captions with English terms break in naive renderers: words flip, "الـ" detaches from its noun, and punctuation lands on the wrong side.

Decision

• Consecutive Latin words merge into one token; a token ending in tatweel (الـ, بـ, للـ) joins the next with NO-BREAK SPACE.
• Each token is an atomic inline-block (white-space: nowrap), so it behaves as one neutral object in the paragraph's bidi resolution; inside it, Latin runs are wrapped in <bdi>.
• Trailing punctuation stays outside the isolate; the chunk's base direction is RTL when it has Arabic.

Consequences

Visual order is correct by construction and verified by geometry tests and golden frames for every case of SRS §9.3. Captions never wrap inside a term.