diff --git a/.claude/project-context.md b/.claude/project-context.md
index 521d842..9db69f2 100644
--- a/.claude/project-context.md
+++ b/.claude/project-context.md
@@ -90,3 +90,8 @@ The workspace should always answer:
 The interface should minimise cognitive load by presenting the current state first and allowing progressively deeper exploration only when requested.
 
 The engine may contain hundreds of reasoning nodes; the user should only see the information required to take the next meaningful action.
+
+## Why workspace layout matters (v0.7)
+
+This phase optimises for simultaneous visibility instead of sequential scrolling.
+Related panels — Understanding alongside Investigation Map, Situation alongside History — can appear side-by-side on wide screens while mobile continues to stack everything vertically. The reasoning engine is completely unaware of these changes; only the presentation layer is affected.
diff --git a/.claude/ux-guidelines.md b/.claude/ux-guidelines.md
index 8f8fa41..bac835b 100644
--- a/.claude/ux-guidelines.md
+++ b/.claude/ux-guidelines.md
@@ -136,6 +136,66 @@ Avoid:
 
 The next question should be the strongest visual element.
 
+## Workspace Layout Philosophy
+
+The Confidence Engine is a workspace, not a document.
+
+Documents optimise for reading from top to bottom.
+
+Workspaces optimise for allowing related information to be visible simultaneously.
+
+As investigations become larger, users should not be forced into unnecessary
+vertical scrolling simply because horizontal space is available.
+
+Layout decisions should always ask:
+
+> "How much useful investigation context can be seen at one time?"
+
+rather than:
+
+> "How narrow can the content column be?"
+
+### Principles
+
+- **Active investigation remains the primary focus.** The current question and response form are always fully visible first.
+- **Frequently referenced information should remain visible.** Understanding and Investigation Map should be scannable without scrolling away from the active question.
+- **Reference material may share horizontal space on larger displays.** Situation and History can sit side-by-side when there is room.
+- **Layout should adapt to available space without changing the investigation flow.** The same information is always present; only its arrangement changes.
+- **Mobile and tablet continue to use a stacked single-column layout.** No progressive disclosure at small sizes — every section remains accessible by scrolling, just as it always has been.
+- **Desktop progressively exposes more simultaneous context.** Instead of simply adding whitespace, wider screens reveal horizontal relationships between related panels.
+
+### Desktop layout model (wide screens)
+
+```
+┌───────────────────── full-width ─────────────────────┐
+│  Investigation Summary                                │
+├───────────────────────────────────────────────────────┤
+│  Active Workspace   │  Working Memory                │
+│  (full width)       │  Understanding     Map        │
+│  Current Investigation                      │         │
+│  Response           └─────────────────────────────────┘
+├───────────────────────────────────────────────────────┤
+│  Reference: Situation    │    History                 │
+├───────────────────────────────────────────────────────┤
+│  Developer Details (always below)                     │
+└───────────────────────────────────────────────────────┘
+```
+
+### Visual goal
+
+The page should feel less like a long report and more like an investigator's
+workspace. The eye should be able to compare Understanding alongside Investigation Map without scrolling, and Situation alongside History in the same way.
+
+### What this phase does NOT include
+
+- No card redesigns.
+- No new navigation.
+- No account management or top bar.
+- No tabs, collapsing layouts, resizable panes, floating panels, or masonry.
+- No typography or colour changes.
+
+This is a layout-only phase. The reasoning engine should remain completely unaware of presentation decisions.
+
 ## TL;DR Workspace Rules
 
 The newest state is the most important state.
diff --git a/components/reasoning-workspace.jsx b/components/reasoning-workspace.jsx
index 636d4e5..8021ccd 100644
--- a/components/reasoning-workspace.jsx
+++ b/components/reasoning-workspace.jsx
@@ -656,10 +656,10 @@ export default function ReasoningWorkspace({
         </div>
       ) : (
         <>
-          {/* ── Investigation summary card ─────────────── */}
+          {/* ── Investigation summary card — always full-width ─────────── */}
           <InvestigationSummaryPanel graph={graph} selectedQuestion={selectedQ} result={result} updateStatus={updateStatus} />
 
-          {/* ── Active investigation context (always visible while question exists) ─ */}
+          {/* Active workspace — primary focus, full-width column ─────── */}
           {hasSelectedQuestion && (
             <>
               <CurrentInvestigationCard selectedQuestion={selectedQ} graph={graph} />
@@ -669,71 +669,82 @@ export default function ReasoningWorkspace({
           {/* Post-update acknowledgement — only after success, never during loading */}
           {updateStatus === "success" && !isUpdating && <UpdateAcknowledgement updateResult={result} />}
 
-          {/* ── Local update loading (always visible when updating) ─ */}
-          {isUpdating && (
-            <LoadingOverlay
-              isLoading={true}
-              elapsed={updateElapsed}
-              currentMessage={updateMsg}
-              variant="update"
-            />
-          )}
-
-          {/* ── Response form — hidden during update loading ─ */}
-          {!isUpdating && canAnswer && (
-            <form onSubmit={handleUpdateCaptureAndSubmit} className="space-y-4 rounded-lg border border-gray-200 bg-white p-5">
-              <div>
-                <label htmlFor="rw-answer" className="mb-2 block text-sm font-medium text-gray-700">
-                  Response
-                </label>
-                <textarea
-                  id="rw-answer"
-                  value={answer}
-                  onChange={(e) => setAnswer(e.target.value)}
-                  rows={4}
-                  disabled={updateStatus === "loading"}
-                  className="w-full rounded-lg border border-gray-300 px-4 py-3 text-sm focus:border-gray-500 focus:outline-none focus:ring-2 focus:ring-gray-400 disabled:cursor-not-allowed disabled:opacity-60"
-                  placeholder="Enter the answer to the selected question..."
+          {/* ── Active workspace (left) + Working memory (right) ─────── */}
+          <div className="grid grid-cols-1 gap-6 md:grid-cols-2">
+            {/* Left column — active workspace */}
+            <div className="space-y-6">
+              {/* ── Local update loading (always visible when updating) ─ */}
+              {isUpdating && (
+                <LoadingOverlay
+                  isLoading={true}
+                  elapsed={updateElapsed}
+                  currentMessage={updateMsg}
+                  variant="update"
                 />
+              )}
+
+              {/* ── Response form — hidden during update loading ─ */}
+              {!isUpdating && canAnswer && (
+                <form onSubmit={handleUpdateCaptureAndSubmit} className="space-y-4 rounded-lg border border-gray-200 bg-white p-5">
+                  <div>
+                    <label htmlFor="rw-answer" className="mb-2 block text-sm font-medium text-gray-700">
+                      Response
+                    </label>
+                    <textarea
+                      id="rw-answer"
+                      value={answer}
+                      onChange={(e) => setAnswer(e.target.value)}
+                      rows={4}
+                      disabled={updateStatus === "loading"}
+                      className="w-full rounded-lg border border-gray-300 px-4 py-3 text-sm focus:border-gray-500 focus:outline-none focus:ring-2 focus:ring-gray-400 disabled:cursor-not-allowed disabled:opacity-60"
+                      placeholder="Enter the answer to the selected question..."
+                    />
+                  </div>
+                  <div className="flex items-center justify-between">
+                    <p className="text-xs text-gray-400">
+                      One update turn only in this prototype.
+                    </p>
+                    <button
+                      type="submit"
+                      disabled={!answer.trim()}
+                      className="rounded-lg bg-blue-700 px-5 py-2.5 text-sm font-medium text-white transition hover:bg-blue-600 disabled:cursor-not-allowed disabled:opacity-40"
+                    >
+                      Update
+                    </button>
+                  </div>
+                </form>
+              )}
+
+              {/* ── Terminal state: outcome card — hidden during update loading ─ */}
+              {!isUpdating && status === "success" && !hasSelectedQuestion && graph && genuineCompletion && (
+                <CompletionCard summary={resolveCurrentSummary(propUnderstanding || graph?.currentSummary || result?.updatedSituationGraph?.currentSummary)} />
+              )}
+              {!isUpdating && status === "success" && !hasSelectedQuestion && graph && !genuineCompletion && (
+                <EvidenceLimitCard summary={resolveCurrentSummary(propUnderstanding || graph?.currentSummary || result?.updatedSituationGraph?.currentSummary)} />
+              )}
+
+            </div>
+
+            {/* Right column — working memory: Understanding + Map */}
+            {hasSelectedQuestion && (
+              <div className="space-y-6">
+                {hasCurrentSummaryCondition && (
+                  <CurrentUnderstandingCard currentSummary={graph?.currentSummary || result?.updatedSituationGraph?.currentSummary} plainLanguage={propUnderstanding || null} />
+                )}
+                <InvestigationMap turnCount={investigationHistory.length} />
               </div>
-              <div className="flex items-center justify-between">
-                <p className="text-xs text-gray-400">
-                  One update turn only in this prototype.
-                </p>
-                <button
-                  type="submit"
-                  disabled={!answer.trim()}
-                  className="rounded-lg bg-blue-700 px-5 py-2.5 text-sm font-medium text-white transition hover:bg-blue-600 disabled:cursor-not-allowed disabled:opacity-40"
-                >
-                  Update
-                </button>
-              </div>
-            </form>
-          )}
+            )}
+          </div>
 
-          {/* ── Terminal state: outcome card — hidden during update loading ─ */}
-          {!isUpdating && status === "success" && !hasSelectedQuestion && graph && genuineCompletion && (
-            <CompletionCard summary={resolveCurrentSummary(propUnderstanding || graph?.currentSummary || result?.updatedSituationGraph?.currentSummary)} />
-          )}
-          {!isUpdating && status === "success" && !hasSelectedQuestion && graph && !genuineCompletion && (
-            <EvidenceLimitCard summary={resolveCurrentSummary(propUnderstanding || graph?.currentSummary || result?.updatedSituationGraph?.currentSummary)} />
-          )}
+          {/* ── Reference row — Situation + History side-by-side on desktop ─ */}
+          <div className="grid grid-cols-1 gap-6 md:grid-cols-2">
+            <OriginalSituation scenario={scenario} centralStatement={graph?.centralStatement} />
+            {investigationHistory.length > 0 && (
+              <InvestigationHistory turns={investigationHistory} />
+            )}
+          </div>
 
-          {/* ── Current understanding (active investigation only) ─ */}
-          {hasCurrentSummaryCondition && hasSelectedQuestion && (
-            <CurrentUnderstandingCard currentSummary={graph?.currentSummary || result?.updatedSituationGraph?.currentSummary} plainLanguage={propUnderstanding || null} />
-          )}
-
-          {/* ── Investigation Map (visible during active investigation) ─ */}
-          {hasSelectedQuestion && (
-            <InvestigationMap turnCount={investigationHistory.length} />
-          )}
-
-          <OriginalSituation scenario={scenario} centralStatement={graph?.centralStatement} />
-
-          {investigationHistory.length > 0 && <InvestigationHistory turns={investigationHistory} />}
-
-          {/* ── Developer details (collapsed by default) ── */}
+          {/* ── Developer details (collapsed by default, always below) ── */}
           {(status === "success" || status === "error") && graph && (
             <DeveloperDetails
               graph={graph}
diff --git a/docs/reasoning-contract-backlog.md b/docs/reasoning-contract-backlog.md
index a165481..e4468d1 100644
--- a/docs/reasoning-contract-backlog.md
+++ b/docs/reasoning-contract-backlog.md
@@ -141,3 +141,5 @@ The current adapter (`lib/map/investigation-map-adapter.js`) uses generic placeh
 6. **Recovery action granularity**: The recovery cards currently offer a single "restart investigation" action. Future engine contracts could support partial recovery (e.g., retry with different parameters, switch models) rather than full restart.
 
 7. **Investigation duration tracking**: The summary panel computes elapsed time from `Date.now() - updatedAt`. If the engine emits proper timestamps, the UI can show accurate elapsed duration and investigate stalls (>5 min between turns).
+
+8. **Layout independence (v0.7 workspace layout phase)**: Reasoning outputs must remain entirely independent of presentation layout. The UI's responsive workspace layout — which progressively reveals simultaneous context on wide screens — is a pure presentation concern. No reasoning contract field should be added, removed, or modified to accommodate layout changes. Future reasoning outputs should carry data semantically; how that data arranges itself visually is the responsibility of the presentation layer alone.