App shell

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<!-- icons: include the icon sheet once per page (see the Setup section, #setup) -->
<div class="app-shell" data-sidebar="open">
  <aside class="app-sidebar" id="app-sidebar">
    <div class="sidebar">
      <div class="sidebar-brand"><span class="sidebar-brand-text">Acme Ops</span></div>
      <nav class="sidebar-nav" aria-label="Primary">
        <ul class="sidebar-nav-list">
          <li><a class="sidebar-nav-link" aria-current="page" href="#"><span class="sidebar-nav-icon"><svg class="icon" aria-hidden="true"><use href="#i-layout-dashboard"/></svg></span><span class="sidebar-nav-label">Dashboard</span></a></li>
          <li><a class="sidebar-nav-link" href="#"><span class="sidebar-nav-icon"><svg class="icon" aria-hidden="true"><use href="#i-receipt"/></svg></span><span class="sidebar-nav-label">Invoices</span></a></li>
        </ul>
      </nav>
    </div>
  </aside>
  <div class="app-content">
    <header class="app-header">
      <div class="topbar">
        <div class="topbar-leading"><button type="button" class="sidebar-toggle" data-sidebar-toggle aria-expanded="true" aria-controls="app-sidebar" aria-label="Toggle navigation"><span class="sidebar-toggle__icon" aria-hidden="true"></span></button></div>
        <div class="topbar-title"><span class="topbar-title-text">Dashboard</span></div>
        <div class="topbar-trailing"><button type="button" class="icon-button" aria-label="Notifications"><svg class="icon" aria-hidden="true"><use href="#i-triangle-alert"/></svg></button></div>
      </div>
    </header>
    <div class="app-main">
      <p class="hm-demo-muted">The routed workspace. The hamburger collapses the sidebar; the state persists via a cookie so the server renders it correctly on the next request.</p>
    </div>
  </div>
</div>

Server exchange

This Hyperpart has no server exchange — it is presentation or client chrome only. htmx does not issue a request on this part's behalf. If you put an affordance (hx-*) on a control that uses this markup, that action's exchange belongs to the action, not this part. See Swap contract for host-owned envelopes.

Swap contract

Agent-visible HTMX topology (ADR-0054 / decision 0012). exchange envelope = what the response may re-emit relative to the persistent slot (body_only | outer | none | host_owned | document). dual-lock validates part markup only — not this envelope. Stem: stems/morph-safe-hypermedia.md; decision: docs/decisions/0012-swap-identity-contract.md.

No host HTMX exchange on this part — presentation or client chrome only. exchange envelope: n/a.

If a host wraps this markup in hx-*, that host owns the swap contract (sole identity + envelope). Prefer innerMorph / outerMorph for stable slots; replacement for flash; body-only responses under inner swaps.

Envelope response examples

This part has no owned exchange (envelope n/a). If a host adds hx-*, that host’s envelope applies — typically body_only:

<!-- Host wraps this presentation part with hx-* (host owns envelope) -->
<!-- Prefer: hx-swap="innerMorph" hx-target="#panel-body" -->
<!-- Server returns body_only interior for #panel-body -->
<div class="dz-stack">content…</div>

Do not re-own the slot:

<!-- WRONG: server returns the presentation root with a new id every poll -->
<div id="app-shell-root" data-dz-region>…</div>

How to use it

Seams

• root data-sidebar=open|closed is SERVER-rendered from the dz_sidebar cookie
• [data-sidebar-toggle] flips state and rewrites the cookie (1y, SameSite=Lax)

Do / Don't

Pitfalls

• cookie not localStorage — the server must paint the correct first state
• the component owns the ≥64rem media query (viewport policy); layout primitives stay MQ-free

Keyboard / AT

• toggle mirrors aria-expanded to the open/closed state
• narrow viewports: sidebar overlays; desktop: persistent rail

Related parts

button sidebar-layout

DOM contract

What the emitted HTML must satisfy — the table is the required surface; Python under contracts/ is the package-internal dual-lock CI runs (tests/test_contracts.py), not an app route. Standalone HTMX4: implement the API so responses match this markup. Dazzle: the agent emits SSR that already satisfies it. Do not invent attrs outside these tables. For request/response wiring see Server exchange.

contracts/app_shell.py

Required in the DOM: root [data-sidebar] (part app-shell). Emit only these attributes — inventing extras is fine only if controllers ignore them; omitting required ones fails CI (tests/test_contracts.py).

Module source

Import path is monorepo/package-local (from contracts._kit import …). Source-token form often uses data-*; gallery demos above are unprefixed. Do not copy this into app routes.

"""HYPERPART: app-shell — DOM contract for the sidebar shell controller."""

from contracts._kit import DomContract, Node, OneOf

DOM_CONTRACT = DomContract(
    part="app-shell",
    root="[data-dz-sidebar]",
    nodes=(
        Node("[data-dz-sidebar]", attrs={"data-dz-sidebar": OneOf("open", "closed")}),
        Node("[data-dz-sidebar-toggle]", attrs={}),
    ),
)

__all__ = ["DOM_CONTRACT"]

Notes

Source files

One logical Hyperpart, 4 code items (CSS layered, JS bundled). Bound by HYPERPART: app-shell — python tools/hyperpart.py app-shell lists them.

site/registry.py · contracts/app_shell.py · components/app-shell.css:1 · controllers/dz-app-shell.js