Refine header emphasis, field-on-layer treatment, and narrow-pane control collapse

docs/IMPLEMENTATION-PLAN.md

@@ -450,7 +450,7 @@ through `services/transfer.ts` (→ `normalizeImport` / envelope build), no moda
   IDB-transaction atomicity would require exposing a raw transaction from `db.ts` — see
   [arch 02](architecture/02-persistence.md)).
 - **A11y:** modal focus trap + return, labelled icon buttons, contrast in both themes (§10) — ✅ in place.
-- **About & Privacy** and **Donate** modals ~~(§01)~~ ✅ (Donate URL is a placeholder
+- **About** and **Donate** modals ~~(§01)~~ ✅ (Donate URL is a placeholder
   `DONATE_URL` pending the real link).
 - **Offline/installable:** the manifest now ships a full SVG icon set (favicon / maskable /
   monochrome) + `theme_color`, and the SW precaches the shell — the app is **installable**.

docs/architecture/09-visual-design.md

@@ -95,12 +95,13 @@ Color is expressed as **roles**, never raw hexes, so themes can repaint the whol
 UI by swapping one set of values. Borrowed from Carbon's layering model:
 
 | Role token                                           | Meaning                                                                                |
-| ---------------------------------------------------- | ----------------------------------------------------------------------------------- |
+| ---------------------------------------------------- | -------------------------------------------------------------------------------------- |
 | `--bg`                                               | App canvas (lowest layer)                                                              |
 | `--layer-01` / `--layer-02`                          | Raised surfaces (panels, cards, popovers) — elevation by lightness step, not shadow    |
 | `--border` / `--border-strong`                       | Subtle and prominent separators                                                        |
 | `--text` / `--text-secondary` / `--text-placeholder` | Text hierarchy                                                                         |
 | `--accent` / `--accent-hover` / `--accent-contrast`  | The expressive accent — **swappable**; UI must never hardcode a hue                    |
+| `--accent-soft` / `--accent-soft-hover`              | Low-emphasis accent **wash** (accent mixed into `--bg`) for a tinted-but-quiet surface |
 | `--focus`                                            | Focus-ring color (defaults to `--accent`)                                              |
 | `--support-error / -success / -warning / -info`      | Status only — color = meaning                                                          |
 
@@ -113,6 +114,17 @@ UI by swapping one set of values. Borrowed from Carbon's layering model:
   warning `#f1c21b`, info `#0043ce` — tuned per theme for contrast.
 - **Contrast:** target WCAG AA (4.5:1 text, 3:1 large/UI). Accent-on-`--bg` and
   text-on-`--accent` must both pass for any shipped theme.
+- **Soft accent is derived, not hardcoded.** `--accent-soft` /
+  `--accent-soft-hover` are `color-mix(in srgb, var(--accent) 12–20%, var(--bg))`,
+  so the wash follows whatever accent + theme is active rather than carrying a
+  per-accent value. Use it for a surface that should be _noticed_ without competing
+  with a primary action (the header's **Donate** button).
+- **Field-on-layer (Carbon layering).** A field is a layer _on top of_ the surface
+  it sits on — so it steps **toward `--bg`**, never to a darker gray. On the white
+  canvas and on a `--layer-01` panel alike, an input reads as **`--bg` fill +
+  `--border-strong` outline**, not a `--layer-02` fill. Stacking a darker-gray field
+  on a gray panel (canvas → `--layer-01` panel → `--layer-02` field) muddies into
+  three indistinct grays — the bug this rule prevents (the snippet metadata panel).
 
 ### 3.4 Shape & elevation
 
@@ -138,9 +150,19 @@ UI by swapping one set of values. Borrowed from Carbon's layering model:
 ## 4. Component conventions
 
 - **Buttons:** square, 32px (compact) / 40px (default) tall. Variants: **primary**
-  (filled `--accent`), **secondary** (bordered), **ghost** (text-only),
+  (filled `--accent`), **secondary** (bordered), **ghost** (text-only, borderless),
-  **danger** (filled `--support-error`). 600-weight label. Clear hover/active and
+  **soft-accent** (ghost on an `--accent-soft` wash — a low-emphasis solicitation,
-  a visible focus ring.
+  e.g. Donate), **danger** (filled `--support-error`). 600-weight label. Clear
+  hover/active and a visible focus ring.
+- **Emphasis hierarchy (Carbon button/usage).** A region carries **one**
+  high-emphasis (primary) button at most; everything else is lower emphasis. In
+  toolbars/headers full of utilities, the utilities go **ghost** so they recede
+  behind the work area and read as a row of equals — only the genuine call to
+  action is filled. Worked examples: the **editor toolbar** (Publish is the lone
+  primary; Extract/Revert are secondary, and collapse to icons when narrow — see
+  [arch 10 §8](10-interaction-and-feedback.md)), and the **header** (Datasets /
+  Import / Export / About are ghost; a divider then sets off the soft-accent Donate
+  and the ghost theme toggle).
 - **Hover is variant-specific:** filled buttons (primary/danger) **darken**
   (`--accent-hover` / a slight brightness drop); outlined/ghost buttons **gain a
   fill one elevation step above their surface** — on `--bg` → `--layer-01`, on a
@@ -150,8 +172,10 @@ UI by swapping one set of values. Borrowed from Carbon's layering model:
   must step its hover fill up to match.
 - **Focus ring:** a 2px `--focus` outline (offset 1–2px). Always visible on
   keyboard focus — accessibility is non-negotiable (principle 4).
-- **Fields** (text, textarea, select, search): square, 1px `--border`, `--layer-01`
+- **Fields** (text, textarea, select, search): square, 1px `--border-strong`,
-  fill, accent border + focus ring on focus. Mono font for spec/JSON inputs.
+  **`--bg` fill** (field-on-layer, §3.3 — white on the canvas _and_ on a
+  `--layer-01` panel; never a darker-gray fill), accent border + focus ring on
+  focus. Mono font for spec/JSON inputs.
 - **List rows** (snippet library): compact, full-row hover (`--layer-01`),
   active row marked by an accent left-border + `--layer-01` fill, secondary
   metadata in `--text-secondary`. Row-level actions reveal on hover.
@@ -233,15 +257,32 @@ Carbon and drawn `fill: currentColor`.
 **Core set** — recurring, cross-surface:
 
 | Meaning              | Carbon glyph    | Form                     | Surfaces                                                                                     |
-| -------------------- | --------------- | --------------------- | ------------------------------------------------- |
+| -------------------- | --------------- | ------------------------ | -------------------------------------------------------------------------------------------- |
 | Close / dismiss      | `Close` (✕)     | icon-only ⭐             | `ModalShell`, `Toaster`                                                                      |
 | Theme → dark         | `Asleep` (moon) | icon-only ⭐             | `ThemeToggle` (shown when light)                                                             |
 | Theme → light        | `Light` (sun)   | icon-only ⭐             | `ThemeToggle` (shown when dark)                                                              |
-| References a dataset | `DataTable`     | icon + text           | Library row marker, Linked-datasets list          |
+| References a dataset | `DataTable`     | icon + text              | Library row marker, Linked-datasets list, header **Datasets**, editor **Extract**⁴           |
-| Add / create-new     | `Add`           | icon + text           | Library "Create New Snippet", Datasets "New …"    |
+| Add / create-new     | `Add`           | icon + text → icon-only⁴ | Library "Create New Snippet" (collapses to "+" when the pane is narrow), Datasets "New …"    |
 | Delete               | `TrashCan`      | icon-only ⭐ (danger)    | Library row delete¹ — text "Delete" in the panel²                                            |
+| Import workspace     | `Upload`        | icon + text              | Header **Import** (a file is brought into the app)                                           |
+| Export workspace     | `Download`      | icon + text              | Header **Export** (the workspace is written out)                                             |
+| About / information  | `Information`   | icon + text              | Header **About**                                                                             |
+| Revert draft         | `Reset`         | icon + text → icon-only⁴ | Editor toolbar **Revert** (restore last published)                                           |
+| Live search          | `Search`        | icon-in-field⁵           | Library search box (leading magnifier; the input's `aria-label`/placeholder names the field) |
+| Settings (gear)      | `Settings`      | icon-only ⭐             | Per-pane settings disclosures (Editor, Preview, Library dates)                               |
 | Unpublished draft    | (CSS dot)       | status-glyph             | Library row (paired with a hidden label)                                                     |
 
+**Pane-toggle set** — the one **custom** sub-family (not single Carbon glyphs): a
+panel frame with one of three regions filled, where the filled bar's _position_
+encodes which pane it toggles. Icon-only by design — position is the meaning — each
+carrying an `aria-label`:
+
+| Meaning             | Glyph                          | Form         | Surface           |
+| ------------------- | ------------------------------ | ------------ | ----------------- |
+| Toggle library pane | panel frame, **left** filled   | icon-only ⭐ | `PaneToggleStrip` |
+| Toggle editor pane  | panel frame, **centre** filled | icon-only ⭐ | `PaneToggleStrip` |
+| Toggle preview pane | panel frame, **right** filled  | icon-only ⭐ | `PaneToggleStrip` |
+
 **Status set** — Carbon's **filled** notification glyphs, one per severity. Unlike
 the outline UI set, these are coloured **by status** (not by surrounding text) and
 are a deliberate _filled_ sub-family. They add a **redundant, non-colour severity
@@ -257,23 +298,37 @@ notifications/validation as they arrive):
 | Success | `CheckmarkFilled`    | `--support-success`     | `Toaster` (success)                         |
 | Info    | `InformationFilled`  | `--support-info`        | `Toaster` (info)                            |
 
-**Scoped set** — registered (glyph reserved) but single-surface and **not yet
+**Scoped set** — single-surface, glyph **reserved** in the ledger but **not yet in
-implemented**:
+the `Icon` registry**:
 
 | Meaning          | Carbon glyph       | Form        | Surface / note                                                                                                                                                                                                                                             |
-| ---------------- | ------------------ | ----------- | ----------------------------------------------------- |
+| ---------------- | ------------------ | ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| Swap / transpose | `ArrowsHorizontal` | icon + text | Chart Builder "Swap X/Y" — one button; icon is polish |
+| Swap / transpose | `ArrowsHorizontal` | icon + text | Chart Builder "Swap X/Y" — the button **ships** today with an interim Unicode `⇄`, not a registry `Icon`. `ArrowsHorizontal` stays reserved here so the meaning is claimed; promote the button to it (add the `IconName` + glyph) when polishing the swap. |
 
-⭐ = **icon-only set**: close + theme (truly universal), plus **delete** as a
+⭐ = **icon-only set** (the glyph alone names the control, via `aria-label`): the
-deliberate destructive-row exception — a dense, repeated list action where a label
+**universal** glyphs `close` + `theme`; the conventional disclosure/affordance
-would cost more than it gives. ✕ means **close only**; delete is `TrashCan`, never
+glyphs `settings` (gear) and the **pane-toggle** trio (position is the meaning);
-✕ (that collision is exactly what one-glyph-one-meaning forbids).
+and **delete** as a deliberate destructive-row exception — a dense, repeated list
+action where a label would cost more than it gives. `search` is _not_ ⭐: its
+magnifier is a decorative lead-in to a labelled input (footnote ⁵), not a control
+named by the glyph. ✕ means **close only**; delete is `TrashCan`, never ✕ (that
+collision is exactly what one-glyph-one-meaning forbids). Admitting a glyph to ⭐ is
+a contract change (§5.1 rule 4), not a per-component call.
 
 ¹ Row delete is hover/focus-revealed and reddens on hover/focus (arch 10 — reveal &
 destructive-intent rules). ² "Duplicate" and "Delete" in the detail panel stay
 **text** (label-first; lower frequency, not a dense row). ³ The raw warning yellow
 fails contrast on light surfaces, so the warning glyph uses `--support-warning-fg`
-(darkened amber; the yellow `--toast-accent` stays on the decorative border).
+(darkened amber; the yellow `--toast-accent` stays on the decorative border). ⁴
+**Responsive collapse**, not membership in the icon-only set: these are icon+text
+that _shed the label_ under width pressure (the editor toolbar's secondary actions,
+and the library's standalone Create CTA, when the pane is narrow — [arch 10
+§8](10-interaction-and-feedback.md)), keeping the accessible name in
+`aria-label`/`title`. A degradation that preserves the name is distinct from a
+permanent icon-only control (§5.1 rule 4), so it isn't a closed-set change. ⁵
+**Icon-in-field**: a decorative leading glyph _inside_ a labelled control — the
+search input's magnifier is `aria-hidden`, and the input itself carries the
+accessible name. Not icon-only (the control is named by its label, not the glyph).
 
 ### 5.3 Size
 

docs/architecture/10-interaction-and-feedback.md

@@ -303,8 +303,10 @@ Carbon search/active-search, NN/g #3. This bullet is the contract; cite it, not
 
 **Resolved — library sort (APG menu-button + NN/g recognition).** The Sort control (spec
 §02) reuses the **disclosure popover** primitive (the settings-popover model above), **not**
-an ARIA menu — but its trigger shows the **current state for recognition** ("Sort: Modified
+an ARIA menu — but its trigger shows the **current state for recognition** ("Modified
-↓"), per NN/g #6 (recognition over recall), instead of a bare gear. Fields are **Modified /
+↓"), per NN/g #6 (recognition over recall), instead of a bare gear. (The visible text drops
+the "Sort:" verb prefix to stay compact in the narrow library rail — §8; the full name
+"Sort by Modified, descending" rides in `aria-label`.) Fields are **Modified /
 Created / Name / Size**; the active field shows a **direction arrow** (↓ desc / ↑ asc) in both
 the trigger and the field row, and the arrow's meaning is mirrored into the field's
 `aria-label` ("Modified, descending") so it isn't carried by the glyph alone. **Selection
@@ -454,6 +456,42 @@ iconography contract, [arch 09 §5](09-visual-design.md).)
 
 ---
 
+## 8. Space-constrained controls (responsive collapse)
+
+The three work panes resize independently, so a toolbar's room is a function of its
+**pane's** width, not the viewport's. Controls must stay usable at the pane minimum
+without clipping, wrapping, or crowding.
+
+- **Query the pane, not the window.** Use a CSS **container query**
+  (`container-type: inline-size` on the row, `@container` on the controls), not a
+  media query — the pane width is what changed. Scope the container to the toolbar
+  row itself, away from heavy children (e.g. the Monaco editor) whose own layout
+  shouldn't inherit size containment.
+- **Shed labels under pressure; keep a contested primary labelled.** When a toolbar
+  would wrap or crowd, **secondary** actions collapse to icon-only and the label
+  moves to `aria-label`/`title`. A **primary that shares the row with secondaries**
+  keeps its text — the label is what marks it as _the_ action to take (the editor
+  toolbar below ~480px: Publish stays "Publish"; Extract/Revert become glyphs). A
+  **standalone primary CTA**, whose prominence is carried by fill + size + position
+  rather than its words, _may_ collapse to a universal-set icon at the pane floor
+  (the library's "Create New Snippet" → "+" below ~250px). Either way it's a
+  degradation that preserves the accessible name — distinct from the closed
+  icon-only set (arch 09 §5.1 rule 4).
+- **Trim a compact trigger's prose, not its state.** A disclosure trigger that names
+  its current state for recognition (NN/g #6) may drop the **verb prefix** to fit a
+  narrow rail — the library Sort trigger shows "Modified ↓", not "Sort: Modified ↓"
+  — but the full name (`aria-label="Sort by Modified, descending"`) is preserved for
+  assistive tech, so only redundant visible words are cut.
+- **A flex control must be able to shrink.** A side control (a Sort button) carries
+  `flex: 0 0 auto` so the flexible field (search) absorbs the slack; the field's
+  `<input>` needs `min-width: 0`, or its intrinsic ~20ch width overflows the slot
+  and overlaps its neighbour. Right-aligned toolbars (`justify-content: flex-end`)
+  clip their **leftmost** item on overflow — left-align so the trimmable end is a
+  settings affordance, not a primary control, and size the pane minimum so it
+  doesn't overflow at all.
+
+---
+
 ## Do / Don't
 
 **Do**

docs/architecture/visual-specimen.html

@@ -87,6 +87,13 @@
         --on-status: #161616;
       }
 
+      /* Soft accent — derived wash (mirrors styles/tokens.css). References --accent
+         + --bg, so it follows whatever accent/theme is active. */
+      [data-theme] {
+        --accent-soft: color-mix(in srgb, var(--accent) 12%, var(--bg));
+        --accent-soft-hover: color-mix(in srgb, var(--accent) 20%, var(--bg));
+      }
+
       /* --- Accent: the FREE, swappable layer (theme-aware). Deep teal is the
          default; see styles/tokens.css for the shipped source of truth. --- */
       [data-accent='teal'] {
@@ -436,6 +443,29 @@
       .btn-ghost:hover {
         background: var(--layer-01);
       }
+      /* Header utility ghost: text-coloured, recedes; hover steps up one layer. */
+      .btn-ghost-util {
+        background: transparent;
+        color: var(--text);
+        gap: var(--space-2);
+      }
+      .btn-ghost-util:hover {
+        background: var(--layer-02);
+      }
+      /* Soft-accent: a low-emphasis accent wash (Donate) — noticed, not shouting. */
+      .btn-soft {
+        background: var(--accent-soft);
+        color: var(--accent-hover);
+      }
+      .btn-soft:hover {
+        background: var(--accent-soft-hover);
+      }
+      .hdr-divider {
+        width: var(--border-width);
+        height: 20px;
+        background: var(--border-strong);
+        margin: 0 var(--space-2);
+      }
       .btn-danger {
         background: var(--support-error);
         color: var(--on-status);
@@ -459,13 +489,16 @@
         font-size: 12px;
         color: var(--text-secondary);
       }
+      /* Field-on-layer (arch 09 §3.3): a field is a layer above its surface, so it
+         steps toward --bg (white) with a --border-strong outline — on the canvas
+         and on a gray panel alike — never a darker-gray fill. */
       .input,
       .select,
       .textarea {
         font: inherit;
         font-size: 14px;
         color: var(--text);
-        background: var(--layer-01);
+        background: var(--bg);
         border: var(--border-width) solid var(--border-strong);
         border-radius: var(--radius);
         padding: var(--space-3) var(--space-4);
@@ -930,6 +963,26 @@
         <p class="cap" style="margin-top: var(--space-4)">
           Tab through to see the focus ring (2px accent outline).
         </p>
+
+        <h3 style="margin-top: var(--space-6)">Emphasis hierarchy — a header cluster</h3>
+        <p class="cap" style="margin-bottom: var(--space-4)">
+          Utilities go <strong>ghost</strong> (icon + text, borderless) so they recede;
+          a divider sets off <strong>Donate</strong> on a <strong>soft-accent</strong> wash
+          — one low-key solicitation, no border. (Carbon: one high-emphasis action per
+          region; utilities at low emphasis.)
+        </p>
+        <div class="row" style="align-items: center">
+          <button class="btn btn-ghost-util sm">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><rect x="8" y="18" width="4" height="2"/><rect x="14" y="18" width="4" height="2"/><rect x="8" y="14" width="4" height="2"/><rect x="14" y="22" width="4" height="2"/><rect x="20" y="14" width="4" height="2"/><rect x="20" y="22" width="4" height="2"/><path d="M27,3H5A2.0025,2.0025,0,0,0,3,5V27a2.0025,2.0025,0,0,0,2,2H27a2.0025,2.0025,0,0,0,2-2V5A2.0025,2.0025,0,0,0,27,3Zm0,2,0,4H5V5ZM5,27V11H27l0,16Z"/></svg>Datasets</button>
+          <button class="btn btn-ghost-util sm">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M26,24v4H6V24H4v4a2,2,0,0,0,2,2H26a2,2,0,0,0,2-2V24Z"/><path d="M6,12l1.41,1.41L15,5.83V24h2V5.83l7.59,7.59L26,12,16,2Z"/></svg>Import</button>
+          <button class="btn btn-ghost-util sm">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M26,24v4H6V24H4v4a2,2,0,0,0,2,2H26a2,2,0,0,0,2-2V24Z"/><path d="M26,14l-1.41-1.41L17,20.17V2H15V20.17l-7.59-7.58L6,14l10,10Z"/></svg>Export</button>
+          <button class="btn btn-ghost-util sm">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M17,22V14H13v2h2v6H12v2h8V22Z"/><path d="M16,8a1.5,1.5,0,1,0,1.5,1.5A1.5,1.5,0,0,0,16,8Z"/><path d="M16,30A14,14,0,1,1,30,16,14,14,0,0,1,16,30ZM16,4A12,12,0,1,0,28,16,12,12,0,0,0,16,4Z"/></svg>About</button>
+          <span class="hdr-divider"></span>
+          <button class="btn btn-soft sm">Donate</button>
+        </div>
       </section>
 
       <!-- FIELDS -->
@@ -1027,10 +1080,48 @@
             <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><rect x="12" y="12" width="2" height="12"/><rect x="18" y="12" width="2" height="12"/><path d="M4,6V8H6V28a2,2,0,0,0,2,2H24a2,2,0,0,0,2-2V8h2V6ZM8,28V8H24V28Z"/><rect x="12" y="2" width="8" height="2"/></svg>
             <span class="cap">delete</span>
           </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M26,24v4H6V24H4v4a2,2,0,0,0,2,2H26a2,2,0,0,0,2-2V24Z"/><path d="M6,12l1.41,1.41L15,5.83V24h2V5.83l7.59,7.59L26,12,16,2Z"/></svg>
+            <span class="cap">import</span>
+          </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M26,24v4H6V24H4v4a2,2,0,0,0,2,2H26a2,2,0,0,0,2-2V24Z"/><path d="M26,14l-1.41-1.41L17,20.17V2H15V20.17l-7.59-7.58L6,14l10,10Z"/></svg>
+            <span class="cap">export</span>
+          </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M17,22V14H13v2h2v6H12v2h8V22Z"/><path d="M16,8a1.5,1.5,0,1,0,1.5,1.5A1.5,1.5,0,0,0,16,8Z"/><path d="M16,30A14,14,0,1,1,30,16,14,14,0,0,1,16,30ZM16,4A12,12,0,1,0,28,16,12,12,0,0,0,16,4Z"/></svg>
+            <span class="cap">info</span>
+          </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M18,28A12,12,0,1,0,6,16v6.2L2.41,18.59,1,20l6,6,6-6L11.59,18.59,8,22.2V16A10,10,0,1,1,18,26Z"/></svg>
+            <span class="cap">revert</span>
+          </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M29,27.5859l-7.5521-7.5521a11.0177,11.0177,0,1,0-1.4141,1.4141L27.5859,29ZM4,13a9,9,0,1,1,9,9A9.01,9.01,0,0,1,4,13Z"/></svg>
+            <span class="cap">search</span>
+          </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><path d="M27,16.76c0-.25,0-.5,0-.76s0-.51,0-.77l1.92-1.68A2,2,0,0,0,29.3,11L26.94,7a2,2,0,0,0-1.73-1,2,2,0,0,0-.64.1l-2.43.82a11.35,11.35,0,0,0-1.31-.75l-.51-2.52a2,2,0,0,0-2-1.61H13.64a2,2,0,0,0-2,1.61l-.51,2.52a11.48,11.48,0,0,0-1.32.75L7.43,6.06A2,2,0,0,0,6.79,6,2,2,0,0,0,5.06,7L2.7,11a2,2,0,0,0,.41,2.51L5,15.24c0,.25,0,.5,0,.76s0,.51,0,.77L3.11,18.45A2,2,0,0,0,2.7,21L5.06,25a2,2,0,0,0,1.73,1,2,2,0,0,0,.64-.1l2.43-.82a11.35,11.35,0,0,0,1.31.75l.51,2.52a2,2,0,0,0,2,1.61h4.72a2,2,0,0,0,2-1.61l.51-2.52a11.48,11.48,0,0,0,1.32-.75l2.42.82a2,2,0,0,0,.64.1,2,2,0,0,0,1.73-1L29.3,21a2,2,0,0,0-.41-2.51ZM25.21,24l-3.43-1.16a8.86,8.86,0,0,1-2.71,1.57L18.36,28H13.64l-.71-3.55a9.36,9.36,0,0,1-2.7-1.57L6.79,24,4.43,20l2.72-2.4a8.9,8.9,0,0,1,0-3.13L4.43,12,6.79,8l3.43,1.16a8.86,8.86,0,0,1,2.71-1.57L13.64,4h4.72l.71,3.55a9.36,9.36,0,0,1,2.7,1.57L25.21,8,27.57,12l-2.72,2.4a8.9,8.9,0,0,1,0,3.13L27.57,20Z"/><path d="M16,22a6,6,0,1,1,6-6A5.94,5.94,0,0,1,16,22Zm0-10a3.91,3.91,0,0,0-4,4,3.91,3.91,0,0,0,4,4,3.91,3.91,0,0,0,4-4A3.91,3.91,0,0,0,16,12Z"/></svg>
+            <span class="cap">settings</span>
+          </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><rect x="4" y="6" width="24" height="2"/><rect x="4" y="24" width="24" height="2"/><rect x="4" y="6" width="2" height="20"/><rect x="26" y="6" width="2" height="20"/><rect x="7" y="10" width="4" height="12"/></svg>
+            <span class="cap">pane-library</span>
+          </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><rect x="4" y="6" width="24" height="2"/><rect x="4" y="24" width="24" height="2"/><rect x="4" y="6" width="2" height="20"/><rect x="26" y="6" width="2" height="20"/><rect x="14" y="10" width="4" height="12"/></svg>
+            <span class="cap">pane-editor</span>
+          </span>
+          <span style="display: inline-flex; flex-direction: column; align-items: center; gap: var(--space-2); color: var(--text-secondary)">
+            <svg width="16" height="16" viewBox="0 0 32 32" style="fill: currentColor"><rect x="4" y="6" width="24" height="2"/><rect x="4" y="24" width="24" height="2"/><rect x="4" y="6" width="2" height="20"/><rect x="26" y="6" width="2" height="20"/><rect x="21" y="10" width="4" height="12"/></svg>
+            <span class="cap">pane-preview</span>
+          </span>
         </div>
         <div class="cap" style="margin-top: var(--space-6)">
-          In context: icon + text is the default; icon-only is the universal/destructive
+          The full Core + pane-toggle set (arch 09 §5.2); the four status glyphs appear,
-          exception. ✕ means close only — delete is the trash glyph.
+          coloured, in the Toasts section below. In context: icon + text is the default;
+          icon-only is the universal/affordance/destructive exception. ✕ means close only —
+          delete is the trash glyph.
         </div>
       </section>
 

docs/spec/01-application-shell.md

@@ -28,17 +28,17 @@ A fixed header spans the top of the app.
 - **Right side**: a row of text entry points. Each opens a destination:
 
 | Entry point | Opens                                                                                                                |
-| --------------- | --------------------------------------------------------------------------------------------------------------- |
+| ----------- | -------------------------------------------------------------------------------------------------------------------- |
 | Import      | A file-picker dialog to choose a previously exported file; the chosen file is imported (see _Import & Export_).      |
 | Export      | Immediately produces a downloaded file containing all snippets and datasets (see _Import & Export_).                 |
 | Datasets    | The Datasets manager modal (see _Datasets_).                                                                         |
-| About & Privacy | The About & Help modal (keyboard shortcuts, about, and privacy information).                                    |
+| About       | The About & Help modal (keyboard shortcuts, about, and privacy information). Labelled "About"; privacy lives inside. |
 | Donate      | The Donate modal.                                                                                                    |
 
 Notes:
 
 - Import and Export act directly (file dialog / file download); they do not open in-app modals.
-- The Datasets, About & Privacy, and Donate entry points each open a modal (see _Modal System_).
+- The Datasets, About, and Donate entry points each open a modal (see _Modal System_).
 - **Settings are not a header entry point.** A design review (see _Settings_) distributed
   preferences to the panes they affect — the appearance theme is a header toggle, and the
   Editor / Performance / Formatting clusters open from a gear control in their own pane. There

src/app/App.module.css

@@ -61,11 +61,20 @@
   flex: 1;
 }
 
-/* Header text-button (Datasets, and future header actions). */
+/*
+ * Header utility buttons (Datasets / Import / Export / About) — low-emphasis
+ * ghost buttons: borderless, icon + label, so they recede behind the work area
+ * and read as a row of equals (Carbon: utilities in toolbars/dashboards belong at
+ * low emphasis). The transparent border holds the box size so hover doesn't shift
+ * neighbours. Matches the ThemeToggle's ghost icon button beside them.
+ */
 .headerButton {
+  display: inline-flex;
+  align-items: center;
+  gap: var(--space-2);
   height: 32px;
-  padding: 0 var(--space-4);
+  padding: 0 var(--space-3);
-  border: var(--border-width) solid var(--border-strong);
+  border: var(--border-width) solid transparent;
   border-radius: var(--radius);
   background: transparent;
   color: var(--text);
@@ -73,11 +82,13 @@
   font-size: 13px;
   font-weight: 500;
   cursor: pointer;
-  transition: background var(--dur-fast) var(--ease);
+  transition:
+    background var(--dur-fast) var(--ease),
+    color var(--dur-fast) var(--ease);
 }
 
 .headerButton:hover {
-  background: var(--layer-01);
+  background: var(--layer-02);
 }
 
 .headerButton:focus-visible {
@@ -85,6 +96,31 @@
   outline-offset: 2px;
 }
 
+/* Vertical rule separating the utilities from Donate + the theme toggle. */
+.headerDivider {
+  flex: 0 0 auto;
+  width: var(--border-width);
+  height: 20px;
+  margin: 0 var(--space-2);
+  background: var(--border-strong);
+}
+
+/*
+ * Donate — the one solicitation in the header. A soft-accent wash lifts it just
+ * above the ghost utilities without competing with a primary action (it carries
+ * no border; the tint alone distinguishes it). Placed after .headerButton:hover
+ * so its own hover state wins the equal-specificity tie.
+ */
+.donate {
+  background: var(--accent-soft);
+  color: var(--accent-hover);
+}
+
+.donate:hover {
+  background: var(--accent-soft-hover);
+  color: var(--accent-hover);
+}
+
 /* The Import file picker is driven programmatically by its header button. */
 .hiddenInput {
   display: none;

src/app/App.tsx

@@ -4,6 +4,7 @@ import { LivePreview } from './components/LivePreview';
 import { ModalShell } from './components/ModalShell';
 import { Onboarding } from './components/Onboarding';
 import { PaneSplitHandle } from './components/PaneSplitHandle';
+import { Icon } from './components/Icon';
 import { PaneToggleStrip } from './components/PaneToggleStrip';
 import { ResizeHandle } from './components/ResizeHandle';
 import { SnippetLibrary } from './components/SnippetLibrary';
@@ -74,6 +75,11 @@ export function App() {
         <h1 className={styles.title}>Astrolabe</h1>
         <span className={styles.version}>v{__APP_VERSION__}</span>
         <span className={styles.spacer} />
+        {/* Header actions establish a hierarchy (Carbon button/usage → one
+            high-emphasis action per region; utilities in dashboards/toolbars read
+            better at low emphasis). The utilities are ghost (borderless) buttons
+            with a leading icon for scanning; a divider then sets off Donate — the
+            one solicitation, given a soft-accent wash — and the theme toggle. */}
         <button
           type="button"
           className={styles.headerButton}
@@ -81,6 +87,7 @@ export function App() {
           aria-keyshortcuts="Meta+K Control+K"
           title="Datasets (⌘/Ctrl+K)"
         >
+          <Icon name="dataset" />
           Datasets
         </button>
         <button
@@ -89,6 +96,7 @@ export function App() {
           onClick={() => fileInputRef.current?.click()}
           title="Import a workspace JSON file"
         >
+          <Icon name="import" />
           Import
         </button>
         <button
@@ -97,6 +105,7 @@ export function App() {
           onClick={() => exportWorkspace()}
           title="Export your workspace to a JSON file"
         >
+          <Icon name="export" />
           Export
         </button>
         <button
@@ -105,11 +114,13 @@ export function App() {
           onClick={() => openModal('about')}
           title="About, keyboard shortcuts, and privacy information"
         >
-          About &amp; Privacy
+          <Icon name="info" />
+          About
         </button>
+        <span className={styles.headerDivider} aria-hidden="true" />
         <button
           type="button"
-          className={styles.headerButton}
+          className={`${styles.headerButton} ${styles.donate}`}
           onClick={() => openModal('donate')}
           title="Support Astrolabe"
         >

src/app/components/Icon.tsx

@@ -29,6 +29,10 @@ export type IconName =
   | 'add' // add / create-new — Carbon Add
   | 'search' // live library search — Carbon Search
   | 'settings' // per-pane settings disclosure (gear) — Carbon Settings
+  | 'import' // import a workspace file — Carbon Upload (a file goes in)
+  | 'export' // export the workspace to a file — Carbon Download (a file comes out)
+  | 'info' // about / information — Carbon Information (outline)
+  | 'revert' // revert draft to last published — Carbon Reset
   // Pane-toggle sub-family (spec §01A): a panel frame with one region filled, so the
   // glyph shows *which* pane it controls by position (left / centre / right).
   | 'pane-library' // toggle the library pane (left)
@@ -69,6 +73,32 @@ const GLYPHS: Record<IconName, ReactNode> = {
       <rect x="12" y="2" width="8" height="2" />
     </>
   ),
+  // Carbon Upload — open tray with an up arrow (a file is brought into the app).
+  import: (
+    <>
+      <path d="M26,24v4H6V24H4v4a2,2,0,0,0,2,2H26a2,2,0,0,0,2-2V24Z" />
+      <path d="M6,12l1.41,1.41L15,5.83V24h2V5.83l7.59,7.59L26,12,16,2Z" />
+    </>
+  ),
+  // Carbon Download — open tray with a down arrow (a file is written out).
+  export: (
+    <>
+      <path d="M26,24v4H6V24H4v4a2,2,0,0,0,2,2H26a2,2,0,0,0,2-2V24Z" />
+      <path d="M26,14l-1.41-1.41L17,20.17V2H15V20.17l-7.59-7.58L6,14l10,10Z" />
+    </>
+  ),
+  // Carbon Information (outline) — ring + "i".
+  info: (
+    <>
+      <path d="M17,22V14H13v2h2v6H12v2h8V22Z" />
+      <path d="M16,8a1.5,1.5,0,1,0,1.5,1.5A1.5,1.5,0,0,0,16,8Z" />
+      <path d="M16,30A14,14,0,1,1,30,16,14,14,0,0,1,16,30ZM16,4A12,12,0,1,0,28,16,12,12,0,0,0,16,4Z" />
+    </>
+  ),
+  // Carbon Reset — a circular arrow, "return to the prior state".
+  revert: (
+    <path d="M18,28A12,12,0,1,0,6,16v6.2L2.41,18.59,1,20l6,6,6-6L11.59,18.59,8,22.2V16A10,10,0,1,1,18,26Z" />
+  ),
   dataset: (
     <>
       <rect x="8" y="18" width="4" height="2" />

src/app/components/LivePreview.module.css

@@ -10,13 +10,22 @@
   flex: 0 0 auto;
   display: flex;
   align-items: center;
-  justify-content: flex-end;
+  /* Fit control hugs the left, settings gear trails right (mirrors the editor
+     toolbar). It used to be flex-end, which made any overflow trim the *left*
+     item — clipping "Original". Left-aligned, the gear is the trimmable end, and
+     the preview's min-width is sized so it never actually overflows. */
+  justify-content: flex-start;
   gap: var(--space-3);
   height: 40px;
   padding: 0 var(--space-4);
   border-bottom: var(--border-width) solid var(--border);
 }
 
+/* Push the settings gear (the last child) to the far right. */
+.header > :last-child {
+  margin-left: auto;
+}
+
 .body {
   position: relative; /* establishes stacking context for the busy overlay */
   flex: 1 1 auto;

src/app/components/SnippetLibrary.module.css

@@ -2,6 +2,10 @@
   display: flex;
   flex-direction: column;
   height: 100%;
+  /* Size-query container so the Create CTA can respond to the pane's own width.
+     `inline-size` (not `size`) leaves block-size uncontained, so the metadata
+     panel's percentage max-height and the list's flex height still resolve. */
+  container-type: inline-size;
 }
 
 /* Library toolbar — heading + date-format settings gear (spec §02 / §07). */
@@ -39,6 +43,9 @@
   color: var(--accent-contrast);
   font: inherit;
   font-weight: 600;
+  /* The label never wraps: above the collapse width the pane is wide enough for one
+     line; below it, only the icon shows. */
+  white-space: nowrap;
   cursor: pointer;
   transition: background var(--dur-fast) var(--ease);
 }
@@ -47,6 +54,16 @@
   background: var(--accent-hover);
 }
 
+/* Narrow pane → the CTA sheds its label and centres the "+" icon (the button stays
+   full-width, so it keeps a large target). The threshold sits comfortably above the
+   216px pane minimum, so the full label is shown across the normal width range and
+   only collapses when the pane is dragged tight. */
+@container (max-width: 250px) {
+  .createNewLabel {
+    display: none;
+  }
+}
+
 /* Search + Sort row, pinned above the list (spec §02). */
 .controls {
   flex: 0 0 auto;
@@ -74,6 +91,10 @@
 
 .searchInput {
   width: 100%;
+  /* Let the input shrink with its flex slot: an <input>'s default min-width is its
+     intrinsic content width (~20ch), which otherwise overflowed the slot and slid
+     over the Sort trigger at the pane minimum. */
+  min-width: 0;
   height: 32px;
   /* Room for the leading magnifier and the trailing clear button. */
   padding: 0 32px 0 32px;
@@ -344,10 +365,14 @@
 .metaComment {
   width: 100%;
   padding: var(--space-2) var(--space-3);
-  border: var(--border-width) solid var(--border);
+  /* A field is a layer *on top of* the panel it sits on (Carbon layering,
+     arch 09 §3.2): on the gray `--layer-01` panel the field goes white with a
+     strong border — matching the search input above — rather than a darker gray,
+     which stacked three muddy grays. */
+  border: var(--border-width) solid var(--border-strong);
   border-radius: var(--radius);
-  background: var(--layer-02, var(--background));
+  background: var(--bg);
-  color: var(--text-primary);
+  color: var(--text);
   font: inherit;
   font-size: 13px;
 }
@@ -390,7 +415,7 @@
 
 .metaTimes dd {
   margin: 0;
-  color: var(--text-primary);
+  color: var(--text);
   white-space: nowrap;
 }
 
@@ -434,10 +459,11 @@
   flex: 1 1 auto;
   height: 32px;
   padding: 0 var(--space-3);
-  border: var(--border-width) solid var(--border);
+  /* White on the gray panel, same field-on-layer treatment as the inputs above. */
+  border: var(--border-width) solid var(--border-strong);
   border-radius: var(--radius);
-  background: var(--background);
+  background: var(--bg);
-  color: var(--text-primary);
+  color: var(--text);
   font: inherit;
   font-size: 12px;
   font-weight: 500;
@@ -449,8 +475,7 @@
 }
 
 .metaAction:hover {
-  background: var(--layer-02, var(--layer-01));
+  background: var(--layer-02);
-  border-color: var(--border-strong, var(--border));
 }
 
 .metaDanger:hover {

src/app/components/SnippetLibrary.tsx

@@ -254,8 +254,17 @@ export function SnippetLibrary() {
       {/* Create raises no toast: the new snippet opens in the editor, so the
           result is already on-screen (spec §02; docs/architecture/10 → Toast
           copy). Delete/duplicate toast because the outcome isn't visible. */}
-      <button className={styles.createNew} onClick={() => createSnippet()}>
+      {/* Primary CTA. When the library pane is dragged narrow the label collapses
-        <Icon name="add" /> Create New Snippet
+          to just the "+" icon (a @container query) so it never wraps to two lines;
+          `aria-label` keeps the accessible name when the text is hidden. */}
+      <button
+        className={styles.createNew}
+        onClick={() => createSnippet()}
+        aria-label="Create New Snippet"
+        title="Create New Snippet"
+      >
+        <Icon name="add" />
+        <span className={styles.createNewLabel}>Create New Snippet</span>
       </button>
 
       {/* Search + Sort controls, pinned above the list (spec §02; council

src/app/components/SortControl.module.css

@@ -2,15 +2,21 @@
 
 .wrap {
   position: relative;
+  /* Never shrink: the search box (flex: 1) absorbs the slack, so the sort trigger
+     keeps its size instead of being squeezed into the search input (which used to
+     overlap it at the pane minimum). */
+  flex: 0 0 auto;
   display: inline-flex;
 }
 
-/* Trigger — shows the current field + direction for recognition (council SORT). */
+/* Trigger — shows the current field + direction for recognition (council SORT).
+   32px tall to match the search input it sits beside (they shared a row at
+   mismatched 28/32px heights before). */
 .trigger {
   display: inline-flex;
   align-items: center;
   gap: var(--space-1);
-  height: 28px;
+  height: 32px;
   padding: 0 var(--space-3);
   border: var(--border-width) solid var(--border-strong);
   border-radius: var(--radius);

src/app/components/SortControl.tsx

@@ -4,9 +4,11 @@
  * A disclosure + non-modal popover, the same APG primitive as SettingsPopover
  * (docs/architecture/10 → "settings are … a disclosure popover") — deliberately
  * NOT an ARIA menu. It differs from SettingsPopover only in its **trigger**: per
- * NN/g recognition-over-recall the trigger shows the current state ("Sort:
+ * NN/g recognition-over-recall the trigger shows the current state ("Modified ↓")
- * Modified ↓") instead of a bare gear, so the user reads the order without
+ * instead of a bare gear, so the user reads the order without opening the popover.
- * opening the popover. The body is a labelled `group` of field buttons (radio
+ * The visible text drops the "Sort:" verb prefix to stay compact in the narrow
+ * library rail; the full name rides in `aria-label` (arch 10 §8). The body is a
+ * labelled `group` of field buttons (radio
  * group), each showing a direction arrow on the active field.
  *
  * Selection model (spec §02): re-selecting the ACTIVE field flips direction;
@@ -121,11 +123,17 @@ export function SortControl() {
         className={styles.trigger}
         aria-expanded={open}
         aria-controls={ID}
-        // Trigger shows current state for recognition (council SORT, NN/g #6).
+        // Trigger shows current field + direction for recognition (council SORT,
+        // NN/g #6) — but without a "Sort:" prefix, so it stays compact beside the
+        // search box in the narrow library pane (the prefix wasted ~36px and
+        // crowded search at the pane minimum). The accessible name keeps the verb
+        // ("Sort by Modified, descending") via aria-label, since the trimmed
+        // visible text ("Modified ↓") would otherwise read as a bare field name.
+        aria-label={`Sort by ${labelFor(sortBy)}, ${sortOrder === 'desc' ? 'descending' : 'ascending'}`}
         title={`Sort by ${labelFor(sortBy)}, ${sortOrder === 'desc' ? 'descending' : 'ascending'}`}
         onClick={() => toggle(ID)}
       >
-        Sort: {labelFor(sortBy)} <span aria-hidden="true">{arrow}</span>
+        {labelFor(sortBy)} <span aria-hidden="true">{arrow}</span>
       </button>
       {open &&
         createPortal(

src/app/components/SpecEditor.module.css

@@ -13,6 +13,10 @@
   height: 40px;
   padding: 0 var(--space-4);
   border-bottom: var(--border-width) solid var(--border);
+  /* Size-query container so the actions below respond to the *pane's* width (the
+     toolbar spans it), not the viewport's. Scoped to the toolbar — not the pane —
+     to keep size containment well clear of the Monaco editor's own layout. */
+  container-type: inline-size;
 }
 
 .spacer {
@@ -47,6 +51,42 @@
   cursor: default;
 }
 
+/* Collapsible secondary actions (Extract, Revert): label by default, icon-only
+   when the pane is narrow. Both children live in the DOM always; the container
+   query swaps which one shows, so there's no reflow cost beyond display. */
+.collapsible {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: var(--space-2);
+}
+
+.actionIcon {
+  display: none;
+}
+
+.actionLabel {
+  display: inline;
+  white-space: nowrap;
+}
+
+/* Below this pane width the labels would crowd Publish / wrap, so the secondary
+   actions shed their text and become square icon buttons (the accessible name +
+   title keep them identifiable). 480px is comfortably above the 384px pane
+   minimum, so the collapse is in effect across the whole narrow range. */
+@container (max-width: 480px) {
+  .collapsible {
+    width: 28px;
+    padding: 0;
+  }
+  .collapsible .actionLabel {
+    display: none;
+  }
+  .collapsible .actionIcon {
+    display: inline-flex;
+  }
+}
+
 .publish {
   border-color: transparent;
   background: var(--accent);

src/app/components/SpecEditor.tsx

@@ -33,6 +33,7 @@ import { notify } from '../stores/NotificationStore';
 import { usePreviewStore } from '../stores/PreviewStore';
 import { selectActiveSnippet, selectShownText, useSnippetStore } from '../stores/SnippetStore';
 import { useUserSettingsStore } from '../stores/UserSettingsStore';
+import { Icon } from './Icon';
 import { SegmentedControl, type SegmentedOption } from './SegmentedControl';
 import {
   NumberControl,
@@ -189,23 +190,33 @@ function EditorToolbar() {
 
       <span className={styles.spacer} />
 
+      {/* Secondary actions collapse to icon-only when the editor pane is narrow
+          (a @container query in the CSS), so "Extract to Dataset" no longer wraps
+          to two lines and Revert/Publish stay on one row. The label rides in
+          `title` (and the accessible name) when only the icon shows. Publish — the
+          one primary action — keeps its label at every width. */}
       {canExtract && (
         <button
           type="button"
-          className={styles.action}
+          className={`${styles.action} ${styles.collapsible}`}
           onClick={() => openModal('extract')}
           title="Extract inline data into a reusable dataset"
+          aria-label="Extract to Dataset"
         >
-          Extract to Dataset
+          <Icon name="dataset" className={styles.actionIcon} />
+          <span className={styles.actionLabel}>Extract to Dataset</span>
         </button>
       )}
       <button
         type="button"
-        className={styles.action}
+        className={`${styles.action} ${styles.collapsible}`}
         onClick={() => void handleRevert()}
         disabled={activeId === null || !dirty}
+        title="Revert draft to the last published version"
+        aria-label="Revert"
       >
-        Revert
+        <Icon name="revert" className={styles.actionIcon} />
+        <span className={styles.actionLabel}>Revert</span>
       </button>
       <button
         type="button"

src/app/stores/PanesStore.test.ts

@@ -40,7 +40,7 @@ describe('clampSideWidth', () => {
   });
 
   test('a container too narrow for all minimums still never drops below the min', () => {
-    // 500px total can't fit library(180)+preview(240)+editor(320)+handles.
+    // 500px total can't fit library(216)+preview(300)+editor(384)+handles.
     expect(clampSideWidth('library', 300, 500, PANE_MIN.preview)).toBe(PANE_MIN.library);
   });
 });
@@ -161,8 +161,8 @@ describe('splitLibraryWidth (editor-hidden library↔preview split, §01A)', ()
   });
 
   test('a span too small for both minimums still keeps the library minimum', () => {
-    // 300px can't fit library(180)+preview(240); the library holds its own min.
+    // 400px can't fit library(216)+preview(300); the library holds its own min.
-    expect(splitLibraryWidth(250, 300)).toBe(PANE_MIN.library);
+    expect(splitLibraryWidth(250, 400)).toBe(PANE_MIN.library);
   });
 });
 
@@ -218,12 +218,13 @@ describe('shownSideWidths (editor re-shown, §01A)', () => {
   });
 
   test('pins the editor width and keeps the ratio set while hidden', () => {
-    // The user re-split to 400:240 while the editor was hidden.
+    // The user re-split to 340:300 while the editor was hidden (both ≥ their
-    const { libraryWidth, previewWidth } = shownSideWidths(PANES_INNER, E, 400, 240, true, true);
+    // minimums, so the rescale preserves the ratio rather than clamping).
+    const { libraryWidth, previewWidth } = shownSideWidths(PANES_INNER, E, 340, 300, true, true);
     // Editor reclaims its slot, so the side panes' combined width is unchanged…
     expect(libraryWidth + previewWidth).toBe(PANES_INNER - E - HANDLES_TOTAL);
-    // …and the 400:240 ratio is preserved (5:3).
+    // …and the 340:300 ratio is preserved.
-    expect(libraryWidth / previewWidth).toBeCloseTo(400 / 240, 5);
+    expect(libraryWidth / previewWidth).toBeCloseTo(340 / 300, 5);
   });
 
   test('no remembered editor width leaves the side widths untouched (legacy/never hidden)', () => {
@@ -263,14 +264,14 @@ describe('editor toggle remembers and restores its width (§01A)', () => {
     store().togglePane('editor', PANES_INNER);
     const captured = store().editorWidth;
     // Drag the library↔preview handle while hidden (setSplit writes both widths).
-    store().setSplit(400, 240);
+    store().setSplit(340, 300);
 
     store().togglePane('editor', PANES_INNER);
     expect(store().editorWidth).toBe(captured); // editor reclaims its slot
     expect(store().libraryWidth + store().previewWidth).toBe(
       PANES_INNER - captured - HANDLES_TOTAL,
     );
-    expect(store().libraryWidth / store().previewWidth).toBeCloseTo(400 / 240, 5);
+    expect(store().libraryWidth / store().previewWidth).toBeCloseTo(340 / 300, 5);
   });
 });
 

src/app/stores/PanesStore.ts

@@ -25,8 +25,17 @@ export type PaneSide = 'library' | 'preview';
 /** Every pane that can be shown/hidden via the toggle strip (spec §01A). */
 export type PaneName = 'library' | 'editor' | 'preview';
 
-/** Minimum widths (px) enforced while resizing, so no pane collapses (§01A). */
+/**
-export const PANE_MIN = { library: 180, preview: 240, editor: 320 } as const;
+ * Minimum widths (px) enforced while resizing, so no pane collapses (§01A).
+ * Tuned so each pane's toolbar stays uncrowded at its floor:
+ * - library 216 — the search box + compact Sort trigger have room to breathe;
+ *   below ~250 the "Create New Snippet" CTA collapses to its icon (container query).
+ * - preview 300 — below ~280 the fit control + settings gear clip, and a chart in
+ *   <300px is too cramped to read.
+ * - editor 384 — gives the JSON real horizontal room (it wrapped hard at 320); the
+ *   toolbar's secondary actions still collapse to icons below ~480.
+ */
+export const PANE_MIN = { library: 216, preview: 300, editor: 384 } as const;
 
 /** Initial side-pane widths (px) on first run, before any persisted layout. */
 export const PANE_DEFAULT = { library: 280, preview: 360 } as const;

styles/tokens.css

@@ -102,6 +102,17 @@
   --accent-hover: #0c5f77;
   --accent-contrast: #ffffff;
 }
+
+/*
+ * Soft accent — a low-emphasis accent wash for a tinted-but-quiet surface (e.g.
+ * the header's Donate button: noticeable without competing with a primary action).
+ * Derived from the swappable accent + the theme background, so it follows any
+ * accent/theme automatically rather than being a hardcoded per-accent value.
+ */
+:root {
+  --accent-soft: color-mix(in srgb, var(--accent) 12%, var(--bg));
+  --accent-soft-hover: color-mix(in srgb, var(--accent) 20%, var(--bg));
+}
 [data-theme='dark'] {
   --accent: #2dd4bf;
   --accent-hover: #5eead4;