diff --git a/frontend/packages/agent/build.mjs b/frontend/packages/agent/build.mjs
index c5e1edfa..be0c3e3a 100644
--- a/frontend/packages/agent/build.mjs
+++ b/frontend/packages/agent/build.mjs
@@ -41,6 +41,10 @@ await build({
   target: ['es2022'],
   sourcemap: true,
   logLevel: 'info',
+  // `@hive/shared/modal.js` imports its shadow-DOM component CSS as raw
+  // text (see dashboard/build.mjs's matching comment) — same reasoning
+  // applies here.
+  loader: { '.css': 'text' },
 });
 
 // Bundle the CSS. `colors.css` re-exports the standalone base16 palette
diff --git a/frontend/packages/agent/src/agent.css b/frontend/packages/agent/src/agent.css
index 6854e3e8..28519eb4 100644
--- a/frontend/packages/agent/src/agent.css
+++ b/frontend/packages/agent/src/agent.css
@@ -6,10 +6,9 @@
    agent SUB-pages (stats, screen) the same back-link nav the dashboard's
    standalone pages use. The live terminal page keeps its own header. */
 @import "@hive/shared/chrome.css";
-/* Themed dialog/toast styles for the shared bindAsyncForms handler + any
-   direct themedConfirm/themedToast calls, so the per-agent UI's
-   confirmations and errors render in-theme instead of unstyled. */
-@import "@hive/shared/modal.css";
+/* Themed dialog/toast component CSS (modal.js) now lives in each
+   component's own shadow root (adoptedStyleSheets), not a global
+   stylesheet — nothing to @import here any more. */
 
 /* ─── full-screen layout overrides ─────────────────────────────────
    The agent page mounts a full-viewport terminal under a fixed
diff --git a/frontend/packages/dashboard/build.mjs b/frontend/packages/dashboard/build.mjs
index 3306f8fe..7276a80a 100644
--- a/frontend/packages/dashboard/build.mjs
+++ b/frontend/packages/dashboard/build.mjs
@@ -74,6 +74,15 @@ await build({
   target: ['es2022'],
   sourcemap: true,
   logLevel: 'info',
+  // `@hive/shared/modal.js` and `hive-btn.js` import their shadow-DOM
+  // component CSS (hive-dialog.css, hive-toast.css, hive-btn.css) as raw
+  // text via a plain `import css from './foo.css'` — the `text` loader turns
+  // that into a string constant at bundle time instead of erroring on an
+  // unrecognised extension. None of these JS entries import a `.css`
+  // file any other way, so this doesn't collide with the separate
+  // page-stylesheet bundling below (`loader: { '.css': 'css' }`), which
+  // runs as its own esbuild invocation over different entry points.
+  loader: { '.css': 'text' },
 });
 
 // Stream-worker entry (#448). Lives in a separate bundle: SharedWorker
diff --git a/frontend/packages/dashboard/src/common.css b/frontend/packages/dashboard/src/common.css
index ae16d272..8922df45 100644
--- a/frontend/packages/dashboard/src/common.css
+++ b/frontend/packages/dashboard/src/common.css
@@ -4,7 +4,6 @@
 @import "@hive/shared/terminal.css";
 @import "@hive/shared/tabs.css";
 @import "@hive/shared/chrome.css";
-@import "@hive/shared/modal.css";
 
 /* ─── global typography ─────────────────────────────────────────────
    Element-level rules shared across all three pages (index, flow,
diff --git a/frontend/packages/shared/package.json b/frontend/packages/shared/package.json
index 41ee6ede..333bcd63 100644
--- a/frontend/packages/shared/package.json
+++ b/frontend/packages/shared/package.json
@@ -17,8 +17,7 @@
     "./chrome.css": "./src/chrome.css",
     "./forms.js": "./src/forms.js",
     "./dom.js": "./src/dom.js",
-    "./modal.js": "./src/modal.js",
-    "./modal.css": "./src/modal.css"
+    "./modal.js": "./src/modal.js"
   },
   "files": [
     "src/"
diff --git a/frontend/packages/shared/src/dom.js b/frontend/packages/shared/src/dom.js
index da314e69..b4b5f4ef 100644
--- a/frontend/packages/shared/src/dom.js
+++ b/frontend/packages/shared/src/dom.js
@@ -5,12 +5,18 @@
 // used).
 //
 // `el(tag, attrs, ...children)` creates an element, applying `attrs` as
-// either the `class`/`html` special cases or plain attributes, and
+// either the `class`/`html`/`is` special cases or plain attributes, and
 // appending `children` (strings become text nodes, `null`/`undefined`
 // entries are skipped so callers can inline conditional children).
+// `is: 'custom-name'` creates a customized built-in element (e.g.
+// `el('button', { is: 'hive-btn' }, 'label')` → `<button is="hive-btn">`)
+// — passed to `document.createElement` itself, since a customized
+// built-in has to be created with its `is` option up front, not upgraded
+// after the fact via `setAttribute`.
 export const el = (tag, attrs = {}, ...children) => {
-  const e = document.createElement(tag);
+  const e = attrs.is ? document.createElement(tag, { is: attrs.is }) : document.createElement(tag);
   for (const [k, v] of Object.entries(attrs)) {
+    if (k === 'is') continue;
     if (k === 'class') e.className = v;
     else if (k === 'html') e.innerHTML = v;
     else e.setAttribute(k, v);
diff --git a/frontend/packages/shared/src/hive-btn.css b/frontend/packages/shared/src/hive-btn.css
new file mode 100644
index 00000000..0d5c96d9
--- /dev/null
+++ b/frontend/packages/shared/src/hive-btn.css
@@ -0,0 +1,40 @@
+/* hive-btn.css — scoped stylesheet for the <hive-btn> customized built-in
+   button element (hive-btn.js). Loaded as raw text at build time
+   (esbuild's `text` loader) and turned into a `CSSStyleSheet` adopted by
+   the element's own shadow root. `:host` styles the button itself (the
+   element *is* a real `<button is="hive-btn">`, so `:host(:hover)` /
+   `:host(:disabled)` select genuine native pseudo-classes, not
+   hand-rolled state tracking) — this is the base look every `<hive-btn>`
+   gets; `variant` is an attribute (not a class) since it's a semantic
+   property of the component, not an arbitrary styling hook. */
+
+:host {
+  font-family: inherit;
+  font-weight: bold;
+  text-transform: uppercase;
+  letter-spacing: 0.1em;
+  background: transparent;
+  -webkit-appearance: none;
+  appearance: none;
+  border: 1px solid;
+  padding: 0.25em 0.8em;
+  cursor: pointer;
+  color: inherit;
+  text-shadow: 0 0 4px currentColor;
+  box-shadow: 0 0 0 0 currentColor;
+  transition: box-shadow 0.15s ease;
+}
+:host(:hover) {
+  background: color-mix(in srgb, var(--fg) 6%, transparent);
+  text-shadow: 0 0 10px currentColor;
+  box-shadow: 0 0 10px -2px currentColor;
+}
+:host(:disabled) {
+  opacity: 0.32;
+  cursor: not-allowed;
+  text-shadow: none;
+  box-shadow: none;
+}
+:host([variant="cancel"]) { color: var(--subtext0); }
+:host([variant="confirm"]) { color: var(--green); }
+:host([variant="danger"]) { color: var(--red); }
diff --git a/frontend/packages/shared/src/hive-btn.js b/frontend/packages/shared/src/hive-btn.js
new file mode 100644
index 00000000..d05b0a48
--- /dev/null
+++ b/frontend/packages/shared/src/hive-btn.js
@@ -0,0 +1,40 @@
+// hive-btn.js — <hive-btn>, a customized built-in `<button>` (`<button
+// is="hive-btn">`) with a shadow root for style encapsulation, replacing
+// the light-DOM `.btn` class as the button primitive for shadow-DOM
+// consumers (starting with modal.js's dialog buttons — see the frontend
+// components-split discussion on the forge issue tracker).
+//
+// Extending `HTMLButtonElement` (a "customized built-in element", not an
+// autonomous one) keeps every native `<button>` behaviour for free —
+// click/keyboard activation, `:disabled`, form participation/submission —
+// instead of re-implementing them on a generic wrapper. The shadow root
+// holds only a `<style>`-equivalent (adopted stylesheet) plus a `<slot>`
+// so the button's light-DOM content (its label, or asyncBtn's swapped-in
+// spinner span) renders through unchanged — slotted content stays styled
+// by the light-DOM cascade (global `.spinner` etc. still apply), only the
+// host element's own box/text styling is shadow-scoped.
+//
+// Customized built-ins aren't supported in Safari/WebKit (a deliberate
+// WebKit-team stance, unlikely to change) — fine here since the project
+// targets recent Firefox only.
+//
+// Usage: `el('button', { type: 'button', is: 'hive-btn', variant: 'danger' }, 'label')`
+// (dom.js's `el()` passes `is` to `document.createElement` so custom-
+// element upgrade happens at creation, not after). `variant` is one of
+// 'cancel' | 'confirm' | 'danger' | (unset, for the neutral/default look)
+// — a plain attribute, not a class, since it's a semantic prop of the
+// component rather than an arbitrary styling hook.
+
+import hiveBtnCss from './hive-btn.css';
+
+class HiveBtn extends HTMLButtonElement {
+  connectedCallback() {
+    if (this.shadowRoot) return; // guard: connectedCallback can re-fire (e.g. re-parenting)
+    const root = this.attachShadow({ mode: 'open' });
+    const sheet = new CSSStyleSheet();
+    sheet.replaceSync(hiveBtnCss);
+    root.adoptedStyleSheets = [sheet];
+    root.append(document.createElement('slot'));
+  }
+}
+customElements.define('hive-btn', HiveBtn, { extends: 'button' });
diff --git a/frontend/packages/shared/src/hive-dialog.css b/frontend/packages/shared/src/hive-dialog.css
new file mode 100644
index 00000000..ec760ddb
--- /dev/null
+++ b/frontend/packages/shared/src/hive-dialog.css
@@ -0,0 +1,73 @@
+/* hive-dialog.css — scoped stylesheet for the <hive-dialog> shadow-DOM
+   custom element (modal.js). Loaded as raw text at build time (esbuild's
+   `text` loader) and adopted via `adoptedStyleSheets`. `:host` styles the
+   element itself, which *is* the fixed-position backdrop — no separate
+   light-DOM backdrop div. Button styling (base look + cancel/confirm/
+   danger variants) lives in hive-btn.css, not here — the dialog's
+   buttons are <hive-btn> elements with their own shadow root. */
+
+:host {
+  position: fixed;
+  inset: 0;
+  z-index: 1000;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 1em;
+  background: color-mix(in srgb, var(--crust) 60%, transparent);
+  -webkit-backdrop-filter: blur(2px);
+  backdrop-filter: blur(2px);
+}
+.box {
+  background: var(--bg-elev);
+  border: 1px solid var(--purple-dim);
+  box-shadow: 0 8px 40px -8px var(--crust);
+  padding: 1.2em 1.4em;
+  max-width: min(32em, 92vw);
+  display: flex;
+  flex-direction: column;
+  gap: 0.9em;
+}
+.title {
+  font-weight: bold;
+  text-transform: uppercase;
+  letter-spacing: 0.08em;
+  color: var(--subtext0);
+}
+.message { color: var(--fg); line-height: 1.45; }
+.checks { display: flex; flex-direction: column; gap: 0.4em; }
+.checkrow {
+  display: flex;
+  align-items: flex-start;
+  gap: 0.5em;
+  cursor: pointer;
+  color: var(--subtext0);
+  font-size: 0.92em;
+  line-height: 1.35;
+}
+.checkrow .check { margin-top: 0.2em; flex: 0 0 auto; }
+.actions {
+  display: flex;
+  justify-content: flex-end;
+  gap: 0.6em;
+  margin-top: 0.2em;
+}
+.promptfield { display: flex; flex-direction: column; gap: 0.4em; }
+.promptlabel { color: var(--subtext0); font-size: 0.9em; }
+.input {
+  font-family: inherit;
+  font-size: 1em;
+  width: 100%;
+  box-sizing: border-box;
+  background: var(--crust);
+  color: var(--fg);
+  border: 1px solid var(--purple-dim);
+  padding: 0.4em 0.6em;
+}
+.input:focus { outline: 1px solid var(--green); }
+.textarea {
+  resize: vertical;
+  min-height: 4.5em;
+  line-height: 1.4;
+  white-space: pre-wrap;
+}
diff --git a/frontend/packages/shared/src/hive-toast.css b/frontend/packages/shared/src/hive-toast.css
new file mode 100644
index 00000000..c4a6d601
--- /dev/null
+++ b/frontend/packages/shared/src/hive-toast.css
@@ -0,0 +1,25 @@
+/* hive-toast.css — scoped stylesheet for the <hive-toast> shadow-DOM
+   custom element (modal.js). Loaded as raw text at build time (esbuild's
+   `text` loader) and adopted via `adoptedStyleSheets`. `:host` styles the
+   element itself, which *is* the visible toast box; `:host(.error)` etc.
+   switch on a plain class the host element carries (set in JS). */
+
+:host {
+  display: block;
+  pointer-events: auto;
+  cursor: pointer;
+  background: var(--bg-elev);
+  border: 1px solid var(--purple-dim);
+  border-left-width: 3px;
+  box-shadow: 0 4px 20px -6px var(--crust);
+  padding: 0.6em 0.9em;
+  font-size: 0.9em;
+  color: var(--fg);
+  white-space: pre-wrap;
+  opacity: 1;
+  transition: opacity 0.2s ease, transform 0.2s ease;
+}
+:host(.out) { opacity: 0; transform: translateX(0.5em); }
+:host(.error) { border-left-color: var(--red); }
+:host(.info) { border-left-color: var(--purple-dim); }
+:host(.ok) { border-left-color: var(--green); }
diff --git a/frontend/packages/shared/src/modal.css b/frontend/packages/shared/src/modal.css
deleted file mode 100644
index aad63efd..00000000
--- a/frontend/packages/shared/src/modal.css
+++ /dev/null
@@ -1,117 +0,0 @@
-/* modal.css — themed dialog component styles.
-   Pairs with modal.js (themedConfirm / themedPrompt / themedToast),
-   whose `<hive-dialog>` / `<hive-toast>` custom elements are styled
-   entirely by class selectors here (light DOM, no shadow root — see the
-   design note atop modal.js). The dialogs are raised from the shared
-   `bindAsyncForms` data-async / data-confirm handler (forms.js), used by
-   both the dashboard and the per-agent UI, so both packages' base
-   stylesheets (common.css / agent.css) @import this to keep the styles
-   present wherever a dialog can fire.
-   (Previously these rules lived in dashboard.css, so dialogs rendered
-   unstyled on standalone dashboard pages such as /core, and the per-agent
-   UI never had them at all — a themed-dialogs consistency fix moved them
-   here and wired both packages' base stylesheets to import this file.) */
-
-.tc-backdrop {
-  position: fixed;
-  inset: 0;
-  z-index: 1000;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  padding: 1em;
-  background: color-mix(in srgb, var(--crust) 60%, transparent);
-  -webkit-backdrop-filter: blur(2px);
-  backdrop-filter: blur(2px);
-}
-.tc-box {
-  background: var(--bg-elev);
-  border: 1px solid var(--purple-dim);
-  box-shadow: 0 8px 40px -8px var(--crust);
-  padding: 1.2em 1.4em;
-  max-width: min(32em, 92vw);
-  display: flex;
-  flex-direction: column;
-  gap: 0.9em;
-}
-.tc-title {
-  font-weight: bold;
-  text-transform: uppercase;
-  letter-spacing: 0.08em;
-  color: var(--subtext0);
-}
-.tc-message { color: var(--fg); line-height: 1.45; }
-.tc-checks { display: flex; flex-direction: column; gap: 0.4em; }
-.tc-checkrow {
-  display: flex;
-  align-items: flex-start;
-  gap: 0.5em;
-  cursor: pointer;
-  color: var(--subtext0);
-  font-size: 0.92em;
-  line-height: 1.35;
-}
-.tc-checkrow .tc-check { margin-top: 0.2em; flex: 0 0 auto; }
-.tc-actions {
-  display: flex;
-  justify-content: flex-end;
-  gap: 0.6em;
-  margin-top: 0.2em;
-}
-.tc-cancel { color: var(--subtext0); }
-.tc-confirm { color: var(--green); }
-.tc-confirm.tc-danger { color: var(--red); }
-
-/* themedPrompt input field */
-.tc-promptfield { display: flex; flex-direction: column; gap: 0.4em; }
-.tc-promptlabel { color: var(--subtext0); font-size: 0.9em; }
-.tc-input {
-  font-family: inherit;
-  font-size: 1em;
-  width: 100%;
-  box-sizing: border-box;
-  background: var(--crust);
-  color: var(--fg);
-  border: 1px solid var(--purple-dim);
-  padding: 0.4em 0.6em;
-}
-.tc-input:focus { outline: 1px solid var(--green); }
-/* themedPrompt's field is always a resizable textarea (Enter submits,
-   Shift+Enter inserts a newline) — sensible min-height, wrapped output. */
-.tc-textarea {
-  resize: vertical;
-  min-height: 4.5em;
-  line-height: 1.4;
-  white-space: pre-wrap;
-}
-
-/* themedToast — non-blocking transient notifications (errors/info/ok) */
-.tc-toasts {
-  position: fixed;
-  top: 1em;
-  right: 1em;
-  z-index: 1100;
-  display: flex;
-  flex-direction: column;
-  gap: 0.5em;
-  max-width: min(28em, 92vw);
-  pointer-events: none;
-}
-.tc-toast {
-  pointer-events: auto;
-  cursor: pointer;
-  background: var(--bg-elev);
-  border: 1px solid var(--purple-dim);
-  border-left-width: 3px;
-  box-shadow: 0 4px 20px -6px var(--crust);
-  padding: 0.6em 0.9em;
-  font-size: 0.9em;
-  color: var(--fg);
-  white-space: pre-wrap;
-  opacity: 1;
-  transition: opacity 0.2s ease, transform 0.2s ease;
-}
-.tc-toast-out { opacity: 0; transform: translateX(0.5em); }
-.tc-toast-error { border-left-color: var(--red); }
-.tc-toast-info { border-left-color: var(--purple-dim); }
-.tc-toast-ok { border-left-color: var(--green); }
diff --git a/frontend/packages/shared/src/modal.js b/frontend/packages/shared/src/modal.js
index 1e860f08..5052a6d8 100644
--- a/frontend/packages/shared/src/modal.js
+++ b/frontend/packages/shared/src/modal.js
@@ -4,27 +4,36 @@
 // actions and prompts match each page's chrome instead of a jarring OS
 // dialog.
 //
-// Implemented as two light-DOM custom elements (`<hive-dialog>`,
-// `<hive-toast>`) — no shadow root, so styling stays exactly where it
-// already lived: the `.tc-*` classes in `modal.css`, imported globally by
-// both packages' base stylesheets. Light DOM was the deliberate call for
-// this first custom-element pilot (see the frontend components-split
-// discussion on the forge issue tracker): it buys lifecycle
-// encapsulation (`connectedCallback`/`disconnectedCallback` own the
-// keydown listener / auto-dismiss timer instead of hand-rolled
-// add/removeEventListener bookkeeping in a closure) without paying the
-// shadow-DOM cost of re-importing every shared stylesheet per instance.
-// If a later pilot wants real style encapsulation, shadow DOM is a
-// drop-in upgrade to these same two classes — the public functional API
-// below (`openDialog`/`themedConfirm`/`themedPrompt`/`themedToast`)
-// wouldn't need to change either way. (Pilot for the frontend
-// components-split proposal — see the forge issue tracker for context.)
+// Implemented as two shadow-DOM custom elements (`<hive-dialog>`,
+// `<hive-toast>`), plus `<hive-btn>` (hive-btn.js) for the dialog's own
+// buttons — real per-component style encapsulation, CSS in real `.css`
+// files imported as raw text (see each component's own header comment
+// for the design rationale: shadow-DOM-vs-light-DOM tradeoffs live atop
+// the `<hive-dialog>`/`<hive-toast>` classes below, the customized-
+// built-in choice lives in hive-btn.js). Other `.btn` consumers across
+// the app stay on the light-DOM `.btn` class for now — migrating them
+// is a separate follow-up.
 //
 // `openDialog` is the general primitive (any title/message/content + a row of
 // buttons); `themedConfirm` is a thin cancel/confirm wrapper with optional
 // checkboxes built on top of it.
 
 import { el } from './dom.js';
+import './hive-btn.js'; // registers <hive-btn> — side-effect import, no named export needed
+import dialogCss from './hive-dialog.css';
+import toastCss from './hive-toast.css';
+
+// Attach an open shadow root to `host`, adopt `ownCssText` (a scoped
+// stylesheet built fresh per call from a real .css file's contents,
+// imported as raw text), and return the shadow root for the caller to
+// populate.
+function attachShadow(host, ownCssText) {
+  const root = host.attachShadow({ mode: 'open' });
+  const sheet = new CSSStyleSheet();
+  sheet.replaceSync(ownCssText);
+  root.adoptedStyleSheets = [sheet];
+  return root;
+}
 
 // <hive-dialog> — the backdrop + box custom element behind `openDialog`.
 // Not exported; constructed and configured by `openDialog` only. Callers
@@ -34,7 +43,9 @@ import { el } from './dom.js';
 // via a `hive-dialog-close` CustomEvent (`detail` = the resolved value)
 // rather than exposing a resolve/reject pair directly — that keeps the
 // element a normal DOM node with a normal event contract instead of a
-// bespoke Promise-ish object.
+// bespoke Promise-ish object. The element itself *is* the backdrop
+// (`:host` carries the fixed-position/centering rules); the box, title,
+// message, content, and buttons all render inside its shadow root.
 class HiveDialog extends HTMLElement {
   connectedCallback() {
     const {
@@ -43,7 +54,8 @@ class HiveDialog extends HTMLElement {
       danger = false, dismissable = true,
     } = this._opts || {};
 
-    this.className = 'tc-backdrop';
+    const root = attachShadow(this, dialogCss);
+
     let settled = false;
     const done = (value) => {
       if (settled) return;
@@ -62,9 +74,13 @@ class HiveDialog extends HTMLElement {
     this._done = done; // exposed for close-on-escape-elsewhere callers, if ever needed
 
     const btnEls = buttons.map((b) => {
+      // `b.class` names the variant ('cancel' | 'confirm'); `b.danger`
+      // overrides it to the 'danger' look regardless (a destructive
+      // confirm button reads as danger, not as a plain confirm).
+      const variant = b.danger ? 'danger' : b.class;
       const btn = el('button', {
-        type: 'button',
-        class: 'btn tc-btn' + (b.class ? ' ' + b.class : '') + (b.danger ? ' tc-danger' : ''),
+        type: 'button', is: 'hive-btn',
+        ...(variant ? { variant } : {}),
       }, b.label);
       btn.addEventListener('click', () => done(b.value));
       return { spec: b, btn };
@@ -72,20 +88,23 @@ class HiveDialog extends HTMLElement {
 
     // Give the dialog an accessible name: label it by its title if present,
     // else by its message, via `aria-labelledby` (a11y — role=dialog needs a
-    // name). Only the labelling element carries the id.
-    const labelId = 'tc-dlg-' + Math.random().toString(36).slice(2, 9);
-    const titleEl = title ? el('div', { class: 'tc-title', id: labelId }, title) : null;
+    // name). Only the labelling element carries the id. IDs are scoped to
+    // this shadow root, so no cross-instance collision risk even without
+    // the random suffix — kept anyway since it costs nothing and guards
+    // against a future shared-DOM edge case (e.g. `::part()` piercing).
+    const labelId = 'dlg-' + Math.random().toString(36).slice(2, 9);
+    const titleEl = title ? el('div', { class: 'title', id: labelId }, title) : null;
     const messageEl = message
-      ? el('div', title ? { class: 'tc-message' } : { class: 'tc-message', id: labelId }, message)
+      ? el('div', title ? { class: 'message' } : { class: 'message', id: labelId }, message)
       : null;
-    const boxAttrs = { class: 'tc-box', role: 'dialog', 'aria-modal': 'true' };
+    const boxAttrs = { class: 'box', role: 'dialog', 'aria-modal': 'true' };
     if (titleEl || messageEl) boxAttrs['aria-labelledby'] = labelId;
     const box = el('div', boxAttrs,
       titleEl,
       messageEl,
       content || null,
-      el('div', { class: 'tc-actions' }, ...btnEls.map((b) => b.btn)));
-    this.append(box);
+      el('div', { class: 'actions' }, ...btnEls.map((b) => b.btn)));
+    root.append(box);
 
     this.addEventListener('click', (e) => {
       if (dismissable && e.target === this) done(null);
@@ -104,11 +123,14 @@ customElements.define('hive-dialog', HiveDialog);
 //   → Promise resolving to the clicked button's `value`, or `null` when the
 //     dialog is dismissed (Escape, backdrop click, or a button whose value is
 //     null). `content` is an optional DOM node rendered between the message
-//     and the buttons (checkboxes, custom fields, …). `buttons` is
-//     `[{ label, value, danger?, class?, autofocus? }]`, rendered
-//     right-aligned. Initial focus: the `autofocus` button if any, else — for
-//     a `danger` dialog — the first non-destructive button (so a stray Enter
-//     can't fire the destructive path), else the last button.
+//     and the buttons (checkboxes, custom fields, …) — built by the caller
+//     with `el()` and appended into the dialog's shadow root once mounted,
+//     same as any other node (a JS-created element isn't bound to a
+//     document/shadow-root until it's actually appended somewhere).
+//     `buttons` is `[{ label, value, danger?, class?, autofocus? }]`,
+//     rendered right-aligned. Initial focus: the `autofocus` button if any,
+//     else — for a `danger` dialog — the first non-destructive button (so a
+//     stray Enter can't fire the destructive path), else the last button.
 export function openDialog(opts = {}) {
   return new Promise((resolve) => {
     const dlg = document.createElement('hive-dialog');
@@ -133,14 +155,14 @@ export function themedConfirm(opts = {}) {
   } = opts;
 
   const boxes = checkboxes.map((cb) => {
-    const input = el('input', { type: 'checkbox', class: 'tc-check', name: cb.name });
+    const input = el('input', { type: 'checkbox', class: 'check', name: cb.name });
     if (cb.checked) input.checked = true;
-    const row = el('label', { class: 'tc-checkrow' },
-      input, el('span', { class: 'tc-check-label' }, cb.label || cb.name));
+    const row = el('label', { class: 'checkrow' },
+      input, el('span', {}, cb.label || cb.name));
     return { input, row };
   });
   const content = boxes.length
-    ? el('div', { class: 'tc-checks' }, ...boxes.map((b) => b.row))
+    ? el('div', { class: 'checks' }, ...boxes.map((b) => b.row))
     : null;
 
   return openDialog({
@@ -149,8 +171,8 @@ export function themedConfirm(opts = {}) {
     content,
     danger,
     buttons: [
-      { label: cancelLabel, value: null, class: 'tc-cancel', autofocus: danger },
-      { label: confirmLabel, value: 'confirm', danger, class: 'tc-confirm', autofocus: !danger },
+      { label: cancelLabel, value: null, class: 'cancel', autofocus: danger },
+      { label: confirmLabel, value: 'confirm', danger, class: 'confirm', autofocus: !danger },
     ],
   }).then((v) => {
     if (v !== 'confirm') return null;
@@ -172,26 +194,30 @@ export function themedPrompt(opts = {}) {
     title = '', message = '', label = '', placeholder = '', value = '',
     confirmLabel = 'ok', cancelLabel = 'cancel',
   } = opts;
-  const input = el('textarea', { class: 'tc-input tc-textarea', rows: '3', placeholder });
+  const input = el('textarea', { class: 'input textarea', rows: '3', placeholder });
   if (value) input.value = value;
   // Enter submits (clicks the confirm button mounted by openDialog);
   // Shift+Enter falls through to the textarea's default newline insert.
+  // `closest()`/`querySelector()` stay within the shadow tree the input
+  // lives in, so this resolves to the dialog's own `.box`/confirm button
+  // without leaking across instances. The confirm button is selected by
+  // its `variant` attribute now (hive-btn.js), not a CSS class.
   input.addEventListener('keydown', (e) => {
     if (e.key === 'Enter' && !e.shiftKey) {
       e.preventDefault();
-      input.closest('.tc-box')?.querySelector('.tc-confirm')?.click();
+      input.closest('.box')?.querySelector('[variant="confirm"]')?.click();
     }
   });
-  const content = el('div', { class: 'tc-promptfield' },
-    label ? el('label', { class: 'tc-promptlabel' }, label) : null,
+  const content = el('div', { class: 'promptfield' },
+    label ? el('label', { class: 'promptlabel' }, label) : null,
     input);
   const result = openDialog({
     title,
     message,
     content,
     buttons: [
-      { label: cancelLabel, value: '__cancel__', class: 'tc-cancel' },
-      { label: confirmLabel, value: '__ok__', class: 'tc-confirm', autofocus: true },
+      { label: cancelLabel, value: '__cancel__', class: 'cancel' },
+      { label: confirmLabel, value: '__ok__', class: 'confirm', autofocus: true },
     ],
   }).then((v) => (v === '__ok__' ? input.value : null));
   // Prefer focusing the field over the OK button once the dialog has mounted.
@@ -204,19 +230,24 @@ export function themedPrompt(opts = {}) {
 // on removal so a toast dismissed early by click doesn't leave a stray
 // timer), rather than the closure-captured timer handle the pre-custom-
 // element version used. Callers set `._message`/`._opts` before append —
-// same reason as `<hive-dialog>` above.
+// same reason as `<hive-dialog>` above. The element itself is the visible
+// toast box (`:host` carries the styling, `:host(.error)` etc. switch on
+// a plain class the host carries) — the message text renders directly in
+// the shadow root rather than via a `<slot>`, since there's no external
+// light-DOM content to project.
 class HiveToast extends HTMLElement {
   connectedCallback() {
     const { type = 'info', duration } = this._opts || {};
     const ms = duration != null ? duration : (type === 'error' ? 8000 : 4000);
-    this.className = 'tc-toast tc-toast-' + type;
+    const root = attachShadow(this, toastCss);
+    this.classList.add(type);
     this.setAttribute('role', type === 'error' ? 'alert' : 'status');
-    this.textContent = this._message || '';
+    root.textContent = this._message || '';
     let removed = false;
     this._remove = () => {
       if (removed) return;
       removed = true;
-      this.classList.add('tc-toast-out');
+      this.classList.add('out');
       setTimeout(() => this.remove(), 200);
     };
     this.addEventListener('click', this._remove);
@@ -233,10 +264,25 @@ customElements.define('hive-toast', HiveToast);
 //   decision (errors, validation, status). Stacks in a fixed top-right
 //   container, auto-dismisses after `duration` ms (errors linger longer), and
 //   can be clicked to dismiss early. `type` ∈ {'info','error','ok'}.
+//   The stack container is a plain positioning wrapper (not itself a
+//   component — no theming, no encapsulation need), so it's styled with a
+//   one-off inline style rather than a stylesheet.
 export function themedToast(message, opts = {}) {
   let container = document.getElementById('tc-toasts');
   if (!container) {
-    container = el('div', { id: 'tc-toasts', class: 'tc-toasts' });
+    container = document.createElement('div');
+    container.id = 'tc-toasts';
+    Object.assign(container.style, {
+      position: 'fixed',
+      top: '1em',
+      right: '1em',
+      zIndex: '1100',
+      display: 'flex',
+      flexDirection: 'column',
+      gap: '0.5em',
+      maxWidth: 'min(28em, 92vw)',
+      pointerEvents: 'none',
+    });
     document.body.append(container);
   }
   const toast = document.createElement('hive-toast');