bg guest body + engine relocation + bare-surface guardrail The gate for SPEC-104: teach bg to host a live sandbox as a bare, full-bleed backdrop. Covers §1–§4 + §7 — the constrained body, the engine relocation that mirrors bg-video, the backdrop posture (mounted-but-inert), the bare-surface guardrail, boot-frame layering, and reduced-motion/off-screen gating. Everything downstream (the preset, the showcase) builds on the data-bg-guest contract this establishes.
high complex
sandbox bg preset (transform-resolved) SPEC-104 §5: make a reusable sandbox backdrop applicable by name (bg="midnight-waves") like any other preset, by adding a sandbox descriptor to BgPresetDefinition — resolved at transform time (not the identity engine, which has no file access), expanding into the WORK-428 data-bg-guest body.
high complex
reveal/stagger engine facet The gate for SPEC-105 (§1–§3): a shared, closed reveal modifier plus an orthogonal stagger modifier on section-level runes, emitting the generic data-* hooks and the per-child index the motion CSS and behaviour read. Pure intent → attributes; no look here.
high moderate
Motion dimension CSS + tokens SPEC-105 §4: a single dimensions/motion.css + motion tokens that render each reveal character — covering all section runes from one stylesheet, with the transform-composition and global-hook rules that keep it from becoming per-rune work.
high moderate
Motion dimension — docs + showcase SPEC-105 §7 + docs: a theme-authoring motion dimension page and an author-facing reveal/stagger reference, plus a feature-stagger demonstration.
medium moderate
Promote reveal motion physics into the theme TokenContract The scroll-reveal physics (WORK-432) shipped as a local :root block in dimensions/motion.css, so a site can only retune them with a raw CSS override. Promote them into the theme's TokenContract so they become first-class, build-validated tokens a site owner adjusts through refrakt.config.json theme.tokens.reveal.* — the same path that already tunes color/radius/spacing.This keeps the SPEC-105 author/theme split intact: physics stay a project/theme-level concern (config, site-wide), never a per-instance Markdown author control.
medium moderate