docs: add UI detail polish design spec

Spec covering radius/spacing tokens, interaction feedback (hover/active/
focus-visible), and a mobile workspace-toolbar wrapping fix, based on
live screenshot review of the running app.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -27,3 +27,6 @@ dist-ssr
 # Backend data and secrets
 data/teaching-books.db
 .env
+
+# Brainstorming visual companion
+.superpowers/

docs/superpowers/specs/2026-06-16-ui-detail-polish-design.md

@@ -0,0 +1,97 @@
+# UI Detail Polish Design
+
+## Goal
+
+Polish UI details across the whole app: interaction feedback, spacing/radius consistency, and a real mobile layout bug in the workspace toolbar. Found via live screenshots of the running app (login, book list, admin, workspace, dialogs) at desktop and 390px mobile width.
+
+## Scope
+
+In scope:
+
+- `src/style.css`: design tokens for border-radius and spacing, transitions, hover/active/focus-visible states, table/sidebar hover tints, mobile toolbar fix.
+- Any component `<style scoped>` blocks that hardcode a radius/spacing value covered by the new tokens (e.g. `AdminPage.vue`, `LoginPage.vue`, dialog components).
+
+Out of scope:
+
+- Replacing native `window.confirm()` (used for delete in `BookListPage.vue` and `AdminPage.vue`) with the app's custom `.dialog` component. This is a behavior/component-level change, not a styling detail — flagged for a future, separate spec.
+- Redesigning the A4 teaching-design canvas or `src/print.css`.
+- Adding icons, animation libraries, or new dependencies.
+- Changing any component's markup structure or behavior, except where strictly required to apply a hover/focus class.
+
+## 1. Radius and Spacing Tokens
+
+Add to `:root` in `src/style.css`:
+
+```css
+--radius-sm: 4px;   /* inline controls: editable-text, markdown-preview/source, board-design, process-step-actions button */
+--radius-md: 6px;   /* default control radius: ui-button, ui-field, ui-select, workspace-toolbar button, dialog-actions button */
+--radius-lg: 8px;   /* cards/surfaces: dialog, login-form */
+--radius-xl: 12px;  /* upload-dropzone */
+--radius-pill: 999px; /* lesson-sidebar-badge */
+--space-1: 4px;
+--space-2: 8px;
+--space-3: 12px;
+--space-4: 16px;
+--space-6: 24px;
+```
+
+Replace existing hardcoded radius values with the matching variable everywhere they appear in `src/style.css` and in component `<style scoped>` blocks (`AdminPage.vue`, `LoginPage.vue`, dialog components). This is a like-for-like swap — current values already map cleanly onto this scale, so visual output should not change except for the spacing snap below.
+
+Snap off-grid spacing values onto the 4px scale where they don't change layout meaningfully:
+
+- `.field` gap `6px` → `var(--space-2)` (8px)
+- `.ui-table th/td` padding `8px 10px` → `var(--space-2) var(--space-2)` (8px 8px)
+- `.objective-row` gap `6px` → `var(--space-2)` (8px)
+
+Skip snapping any value where it would visibly break an intentional layout (e.g. `process-step-actions { width: 6em }` is a width, not a spacing token, and stays as-is).
+
+## 2. Interaction Feedback (subtle intensity)
+
+Apply `transition: background-color .15s ease, border-color .15s ease, box-shadow .15s ease;` to:
+
+- `.ui-button` (covers `--primary` and `--danger` variants)
+- `.workspace-toolbar button`
+- `.dialog-actions button`
+- `.process-step-actions button`
+- `.editable-text`, `.markdown-preview` (already have hover background, currently instant)
+
+Add `:active:not(:disabled)` states (one shade darker / more saturated than hover) to the same button selectors above, so clicks feel acknowledged.
+
+Add hover feedback where there is currently none:
+
+- `.lesson-sidebar-select:not(.lesson-sidebar-item--active *)`: light neutral hover background (e.g. `#f4f6f7`), distinct from the existing green `--active` state, transition included.
+- `.ui-table tbody tr:hover`: light tint (e.g. `var(--green-100)` at reduced opacity or `#f8faf9`) for scanability.
+
+Add a shared `:focus-visible` style for buttons, matching the existing `.ui-field:focus` treatment (`border-color: var(--green-600); box-shadow: 0 0 0 2px rgba(45, 122, 88, 0.16);`) so keyboard focus is visually consistent between buttons and inputs. Mouse clicks should not trigger this (hence `:focus-visible`, not `:focus`).
+
+## 3. Mobile Workspace Toolbar Fix
+
+Current bug: `.workspace-toolbar` is a fixed-height (56px) single-row flex container with no wrapping. At ~390px width its 6 buttons compress until button text wraps character-by-character, making the toolbar unreadable and unusable.
+
+Fix (selected option B — wrap): add a breakpoint at `max-width: 600px`:
+
+```css
+@media (max-width: 600px) {
+  .workspace-toolbar {
+    height: auto;
+    flex: 0 0 auto;
+    flex-wrap: wrap;
+    padding: var(--space-2) var(--space-4);
+    gap: var(--space-2);
+  }
+  .workspace-toolbar button {
+    flex: 0 0 auto;
+  }
+  .workspace-toolbar-count {
+    flex: 1 1 100%;
+  }
+}
+```
+
+Verified by live injection at 390px: all 6 buttons stay on readable single-line labels across two rows, count text drops to its own line below.
+
+## Testing
+
+- Run existing component tests (no behavior or markup changes expected to break them).
+- Run `bun run build` (includes `vue-tsc -b`) to confirm no type errors from any `<style scoped>` edits.
+- Manually verify in the browser at desktop width and at 390px width (workspace toolbar, sidebar hover, table hover, button focus-visible ring).