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`fancy_animations: false` and `low_motion: true` already exist on the settings struct, but the flag was undocumented and the only ways to opt in were the `/settings` slash command or hand-editing `~/.config/deepseek/settings.toml` — there was no environment- level signal that platform a11y tooling could carry forward. * `NO_ANIMATIONS=1` env var now forces `low_motion = true` and `fancy_animations = false` at startup, regardless of what's on disk. Recognises `1`, `true`, `yes`, `on` (case-insensitive); any other value is treated as unset. * `Settings::apply_env_overrides()` is now called at the end of `Settings::load()`, so every consumer (App::new, /config, the doctor surface) sees the override applied uniformly. The override is a startup-time overlay — changing the env var mid-session has no effect. * New `docs/ACCESSIBILITY.md` documents the existing `low_motion`, `fancy_animations`, `calm_mode`, `show_thinking`, and `show_tool_details` toggles plus the `NO_ANIMATIONS` startup override. Includes guidance for screen-reader users and a link back to this issue for follow-up motion regressions. Tests: 3 new tests in `settings.rs` (force-low-motion-on, override- user-opt-in, truthy-spelling-recognition). All three serialise through a static Mutex so the cargo parallel runner doesn't observe interleaved env mutations.