/**
* @todayai-labs/tck-host/style — host-side baseline contract.
*
* Every TCK consumer (workbench, apps/web embed shell, future
* macOS WKWebView host) ``s this stylesheet so the bits the
* widget bundler deliberately strips from each `.tckb`'s
* `widget.css` are present on the host: a baseline reset, theme
* tokens, and the `[data-theme='dark']` variant binding that
* bundled widgets compile against.
*
* It does NOT ship Tailwind's element-level preflight (the
* `h1…/p/button/img/…` reset rules) — only a minimal baseline:
* a `box-sizing` reset, an `html, body` reset, design tokens,
* the `[data-theme]` swaps, and the feed-chrome classes. A host
* that needs element preflight supplies it via its own
* `@import 'tailwindcss'` (host-playground does this at
* `src/index.css`); a pure-light-DOM host that ``s only
* this file gets none.
*
* No utility classes ship here — utilities are the widget's
* responsibility, delivered inside `widget.css` and adopted into the
* widget's shadow root. The host's job is to provide:
*
* - A `box-sizing` reset so widget JSX layout works as authored.
* - `--tck-columns` / `--tck-gap` / `--tck-cell` defaults the
* canvas reads (hosts override per breakpoint via media query).
* - `--tck-radius-*` tokens for chrome-side rounded surfaces.
* - `--font-sans` as a system stack. Consumers wanting a brand
* face override `--font-sans` on the host element before
* loading this stylesheet.
* - Light/dark token pairs swapped via `[data-theme='dark']`.
* The attribute lives on `` and is the canonical theme
* surface across the TCK ecosystem (bundler, preview,
* workbench, embed shell). Host-specific theming conventions
* (`html.dark`, OS prefers-color-scheme, etc.) don't reach
* widgets — only `[data-theme]` does.
*
* # Scoping — `data-tck-host` sentinel (host-style@0.5.0+)
*
* Before 0.5.0 this stylesheet declared its reset, tokens, and
* theme rules at bare `:root` / `html, body` / `*` selectors,
* leaking the box-sizing reset, the body-color override, and the
* full Tailwind v4 stock palette into consumer documents that
* ``'d the file. apps/web users on todayai.dev surfaced the
* leak (Task #32): the Tailwind palette and `--font-sans` override
* showed up on the document `` even on non-TCK routes.
*
* Post-0.5.0 every leak-prone rule is wrapped in
* `:where([data-tck-host])`. Consumers MUST mark the ancestor of
* their widget mount point with `data-tck-host`; the box-sizing
* reset, the typography reset, the design tokens, and the
* Tailwind palette all cascade to descendants of that element
* (and only those descendants).
*
* - Full-document hosts (embed shells, the workbench): add
* `data-tck-host` to ``. Behavior matches pre-0.5.0.
* - Scoped hosts (apps/web `` inside the opal
* chrome): add `data-tck-host` to the canvas mount div
* (`#canvas-feed-root`). Only the canvas subtree sees the
* reset + tokens; the opal chrome's own typography and box
* sizing stay independent.
*
* `:where(...)` carries zero specificity, so consumer overrides
* (a brand font-family on the host element, a custom
* `--font-sans`, a different background) still win on collision.
*
* Cascade order consumers should produce:
* 1. host-base.css (this file — baseline reset + tokens
* under `:where([data-tck-host])`)
* 2. per-widget widget.css (fetched at mount and adopted inside
* the widget shadow root; selectors
* match only widget DOM)
* 3. host-chrome.css (the consumer's own card surface,
* gradient, page-level decoration)
*/
:where([data-tck-host]),
:where([data-tck-host]) *,
:where([data-tck-host]) *::before,
:where([data-tck-host]) *::after {
box-sizing: border-box;
}
/* Transparent-canvas declaration is NOT here. The load-bearing
* `html, body { background: transparent }` rule emits from
* `getHostHeadNodes` (`bootstrap/get-host-head-nodes.tsx`) as a
* dedicated `