Network/Register/Customization Theme System And Content Security
Gap Register
G-050Public

Customization theme system and user-content security

Tier 2 — Structurally thin, not launch-blocking
Status
Open — token model decided (Entry 037); content-security open
Owner
Creator
Why now
The theme token model is now decided (Entry 037): a theme is validated design tokens plus a checked asset bundle, no arbitrary CSS/JS. The raw-HTML personal-space tier still needs its isolated domain, scoping model, and CSP posture before it is built.
Related
Entry 027

Specify the declarative theme-token schema and per-scope CSS isolation, plus the isolated user-content domain (registration + PSL) for the raw-HTML tier.

Why this matters

Entry 027 decides the shape (declarative cascade on the main origin; raw HTML on an isolated origin), and Entry 037 fixes the theme execution boundary: a theme is validated design tokens + a checked asset bundle — never arbitrary CSS or JS, distributed through a marketplace over that safe substrate. This entry specifies the remaining mechanics:

  • Theme-token schema — the CSS custom properties exposed at each cascade rung (network / franchise / community), and the allowlisted asset types (backgrounds, wordmarks, fonts).
  • Scope isolation — how a franchise or community theme is confined to its subtree (e.g. data- attribute scoping or shadow DOM) so it cannot bleed into canon pages or other communities, and never overlays the network chrome.
  • Isolated user-content domain — selecting the separate registrable domain for the raw-HTML tier (per-user subdomain), submitting it to the Public Suffix List, and the CSP / sandbox posture there.
  • Uploaded files — the cookieless usercontent origin for avatars and attachments, with sanitized content-types.
  • Abuse and performance limits — payload sizes, script/network limits in the sandbox, and review/takedown hooks.

Related

  • Entry 027 — Atlas customization ladder (the shape)
  • Entry 037 — Inline UGC CMS architecture (the decided theme/plugin boundary)