diff --git a/.claude/ux-guidelines.md b/.claude/ux-guidelines.md
index 5ea2c05..a2fb143 100644
--- a/.claude/ux-guidelines.md
+++ b/.claude/ux-guidelines.md
@@ -348,3 +348,24 @@ Returning users should control repeated guidance.
 The workspace should remain the primary visual focus.
 
 Information should naturally flow from left to right.
+
+## Attention Hierarchy
+
+The current task always owns the user's attention.
+
+Supporting information should remain available without competing.
+
+Visual emphasis should come primarily from hierarchy rather than colour.
+
+Reduce distraction before adding decoration.
+
+Calm interfaces improve reasoning.
+
+Hierarchy flows from strongest to quietest:
+
+1. The current investigation question (strongest visual element)
+2. The response area (interactive, clear action)
+3. Supporting context (visible but restrained)
+4. Reference material (available, low priority)
+
+The workspace should feel like an active desk — the work in progress is prominent, supporting tools are within reach but not shouting for attention.
diff --git a/components/investigation-map.jsx b/components/investigation-map.jsx
index e220a83..210afbc 100644
--- a/components/investigation-map.jsx
+++ b/components/investigation-map.jsx
@@ -82,15 +82,15 @@ export default function InvestigationMap({ turnCount = 0 }) {
   if (!hasActiveTopics && groups.established.length === 0) return null;
 
   return (
-    <div className="rounded-lg border border-gray-100 bg-gray-50/50 p-4" role="region" aria-label="Investigation map preview">
-      <h2 className="mb-1 text-sm font-semibold tracking-tight text-gray-400">
+    <div className="rounded-lg border border-gray-200/60 bg-gray-50/30 p-4" role="region" aria-label="Investigation map preview">
+      <h2 className="mb-1 text-[11px] font-medium tracking-widest uppercase text-gray-300">
         Investigation Map
       </h2>
-      <p className="mb-3 text-xs text-gray-400">
+      <p className="mb-3 text-xs text-gray-400/70">
         Active investigation topics and their status.
       </p>
 
-      <div className="space-y-px border-t border-gray-100 pt-3" role="list" aria-label="Investigation topics">
+      <div className="space-y-px border-t border-gray-200/60 pt-3" role="list" aria-label="Investigation topics">
         {topics.map((topic, i) => (
           <TopicRow key={`${topic.title}-${i}`} title={topic.title} status={topic.status} />
         ))}
diff --git a/components/investigation-summary-panel.jsx b/components/investigation-summary-panel.jsx
index 072cdbd..09ec9ae 100644
--- a/components/investigation-summary-panel.jsx
+++ b/components/investigation-summary-panel.jsx
@@ -62,10 +62,10 @@ function InvestigationSummaryPanel({ graph, selectedQuestion, result, updateStat
   }
 
   const statusColors = {
-    idle:        { border: "border-gray-200",   bg: "bg-gray-50",    text: "text-gray-600" },
-    investigating: { border: "border-blue-200",  bg: "bg-blue-50",   text: "text-blue-700" },
-    complete:    { border: "border-green-200",   bg: "bg-green-50",  text: "text-green-700" },
-    limit:       { border: "border-gray-300",    bg: "bg-gray-100",  text: "text-gray-500" },
+    idle:        { border: "border-gray-200/60",   bg: "bg-gray-50/40",    text: "text-gray-400" },
+    investigating: { border: "border-blue-200/60",  bg: "bg-blue-50/30",   text: "text-blue-600" },
+    complete:    { border: "border-green-200/60",   bg: "bg-green-50/30",  text: "text-green-600" },
+    limit:       { border: "border-gray-200",    bg: "bg-gray-50/40",  text: "text-gray-400" },
   };
 
   const colors = statusColors[currentStatus.level] || statusColors.idle;
@@ -125,10 +125,10 @@ function InvestigationSummaryPanel({ graph, selectedQuestion, result, updateStat
       {/* Current understanding */}
       {currentUnderstanding && (
         <div>
-          <h3 className="mb-1 text-xs font-bold uppercase tracking-wider text-gray-400">
+          <h3 className="mb-1 text-[11px] font-medium tracking-widest uppercase text-gray-400/70">
             What we understand so far
           </h3>
-          <p className="text-sm leading-relaxed text-gray-700">{currentUnderstanding}</p>
+          <p className="text-sm leading-relaxed text-gray-600">{currentUnderstanding}</p>
         </div>
       )}
 
diff --git a/components/reasoning-workspace.jsx b/components/reasoning-workspace.jsx
index bb1c708..67868be 100644
--- a/components/reasoning-workspace.jsx
+++ b/components/reasoning-workspace.jsx
@@ -99,8 +99,8 @@ function UnexpectedStateCard({ stateName, onRetry, onRestart }) {
 
 function ContinueLaterBanner({ onRestart }) {
   return (
-    <div className="rounded-lg border border-blue-200 bg-blue-50 px-5 py-4 text-center">
-      <p className="text-sm text-blue-800">
+    <div className="rounded-lg border border-blue-200/60 bg-blue-50/40 px-5 py-4 text-center">
+      <p className="text-sm text-blue-700/70">
         Your previous investigation state is still saved. You can continue where you left off or start fresh.
       </p>
       {onRestart && (
@@ -248,13 +248,13 @@ function CurrentInvestigationCard({ selectedQuestion, graph }) {
   }
 
   return (
-    <div className="investigation-card rounded-lg border-2 border-green-300 bg-green-50 p-6">
-      <h2 className="mb-2 text-sm font-bold tracking-wide text-green-700">
+    <div className="investigation-card rounded-lg border-[2.5px] border-green-400 bg-gradient-to-b from-green-50 to-white p-8 shadow-sm">
+      <h2 className="mb-3 text-xs font-bold tracking-widest uppercase text-green-600/70">
         Investigation
       </h2>
-      <p className="text-xl font-semibold leading-snug text-gray-900">{q}</p>
+      <p className="text-2xl font-semibold leading-tight text-gray-900">{q}</p>
       {whyMattersText && (
-        <p className="mt-4 text-sm leading-relaxed text-green-800">
+        <p className="mt-5 text-sm leading-relaxed text-green-800/80">
           {whyMattersText}
         </p>
       )}
@@ -317,11 +317,11 @@ function CurrentUnderstandingCard({ currentSummary, plainLanguage }) {
   if (!summary) return null;
 
   return (
-    <div className="rounded-lg border border-gray-100 bg-white px-6 pt-5 pb-6">
-      <h2 className="mb-4 text-xl font-semibold tracking-tight text-gray-800">
+    <div className="rounded-lg border border-gray-200/60 bg-white/80 px-6 pt-5 pb-6">
+      <h2 className="mb-4 text-base font-semibold tracking-tight text-gray-400">
         Understanding
       </h2>
-      <p className="text-sm leading-relaxed text-gray-700">{summary}</p>
+      <p className="text-sm leading-relaxed text-gray-600">{summary}</p>
     </div>
   );
 }
@@ -331,11 +331,11 @@ function PlainLanguageCard({ summary }) {
   if (!summary) return null;
 
   return (
-    <div className="rounded-lg border border-gray-100 bg-white px-6 pt-5 pb-6">
-      <h2 className="mb-4 text-xl font-semibold tracking-tight text-gray-800">
+    <div className="rounded-lg border border-gray-200/60 bg-white/80 px-6 pt-5 pb-6">
+      <h2 className="mb-4 text-base font-semibold tracking-tight text-gray-400">
         Understanding
       </h2>
-      <p className="text-sm leading-relaxed text-gray-700">{summary}</p>
+      <p className="text-sm leading-relaxed text-gray-600">{summary}</p>
     </div>
   );
 }
@@ -352,7 +352,7 @@ function InvestigationHistoryCard({ turn }) {
 
   return (
     <details
-      className="rounded-lg border border-gray-100 bg-gray-50/60"
+      className="rounded-lg border border-gray-200/60 bg-gray-50/30"
       key={turn.id}
       open={!isCollapsed}
       data-testid="investigation-turn"
@@ -383,7 +383,7 @@ function InvestigationHistory({ turns }) {
 
   return (
     <div className="space-y-3" data-testid="investigation-history">
-      <h2 className="text-xs font-semibold tracking-wider text-gray-400">
+      <h2 className="text-[11px] font-medium tracking-widest uppercase text-gray-300">
         History
       </h2>
       <div className="space-y-2">
@@ -402,12 +402,12 @@ function OriginalSituation({ scenario, centralStatement }) {
   if (!text) return null;
 
   return (
-    <div className="rounded-lg border border-gray-100 bg-gray-50/70 px-5 py-4">
-      <h2 className="mb-2 text-xs font-semibold tracking-wider text-gray-400">
+    <div className="rounded-lg border border-gray-200/60 bg-gray-50/40 px-5 py-4">
+      <h2 className="mb-2 text-[11px] font-medium tracking-widest uppercase text-gray-300">
         Situation
       </h2>
 
-      <p className="whitespace-pre-wrap text-sm leading-relaxed text-gray-700">
+      <p className="whitespace-pre-wrap text-sm leading-relaxed text-gray-600">
         {text}
       </p>
     </div>
@@ -440,7 +440,7 @@ function UpdateAcknowledgement({ updateResult }) {
       className="transition-all duration-1500 ease-in"
       style={{ opacity: visible ? 0.7 : 0, maxHeight: visible ? "4rem" : "0", marginBottom: visible ? "1rem" : "0" }}
     >
-      <div className="rounded-lg border border-blue-200 bg-blue-50/60 px-4 py-2 text-xs text-blue-800">
+      <div className="rounded-md border border-blue-200/60 bg-blue-50/30 px-4 py-2 text-xs text-blue-700/60">
         {summary}
       </div>
     </div>
@@ -450,11 +450,11 @@ function UpdateAcknowledgement({ updateResult }) {
 // ── Developer details disclosure ──────────────────────────────
 function DeveloperDetails({ graph, selectedQuestion, diagnostics, newlySurfacedNodeIds, updateResult }) {
   return (
-    <details className="rounded-lg border border-gray-200 bg-gray-50">
-      <summary className="cursor-pointer px-5 py-3 text-sm font-medium text-gray-600 hover:text-gray-800">
+    <details className="rounded-lg border border-gray-200/60 bg-gray-50/30">
+      <summary className="cursor-pointer px-5 py-3 text-sm font-medium text-gray-400 hover:text-gray-600">
         Developer details
       </summary>
-      <div className="border-t border-gray-200 px-5 pb-4 pt-3 space-y-4">
+      <div className="border-t border-gray-200/60 px-5 pb-4 pt-3 space-y-4">
         {graph && (
           <SituationGraphView
             situationGraph={graph}
@@ -482,13 +482,13 @@ function LoadingOverlay({ isLoading, elapsed, currentMessage, variant }) {
   }
 
   return (
-    <div className="rounded-lg border border-gray-200 bg-blue-50 px-5 py-6" role="status" aria-busy="true" data-testid="loading-overlay">
+    <div className="rounded-lg border border-blue-200/60 bg-blue-50/40 px-6 py-7" role="status" aria-busy="true" data-testid="loading-overlay">
       <div className="flex items-center gap-3">
         <ActivitySpinner />
-        <span className="text-base font-medium text-blue-900">Working through your situation</span>
+        <span className="text-base font-medium text-blue-800/70">Working through your situation</span>
       </div>
-      <p className="mt-2 text-sm text-blue-700">{statusText}</p>
-      <p className="mt-1 text-xs text-blue-500" aria-live="polite">
+      <p className="mt-3 text-sm text-blue-600/60">{statusText}</p>
+      <p className="mt-2 text-xs text-blue-400/50" aria-live="polite">
         This has been running for {elapsed}s.
         {variant === "initial" && elapsed >= 45 && (
           <span className="block mt-1">This can take around a minute with the current local model.</span>
diff --git a/components/scenario-form.jsx b/components/scenario-form.jsx
index 17b6738..e609d56 100644
--- a/components/scenario-form.jsx
+++ b/components/scenario-form.jsx
@@ -395,18 +395,18 @@ export default function ScenarioForm() {
             {/* Left panel — Facilitator (1/3 on desktop) */}
             {!hideFacilitatorOnLanding && (
               <div className="md:col-span-1">
-                <div className="rounded-lg border border-gray-100 bg-gray-50/60 px-6 pt-5 pb-6 sticky top-6">
-                  <h2 className="mb-3 text-sm font-semibold tracking-wide text-gray-500 uppercase">Before we begin</h2>
-                  <p className="text-sm leading-relaxed text-gray-700 mb-4">
+                <div className="rounded-lg border border-amber-200/60 bg-gradient-to-b from-amber-50/60 to-white px-8 pt-7 pb-7 sticky top-6 shadow-sm">
+                  <h2 className="mb-4 text-xs font-bold tracking-widest uppercase text-amber-600/60">Before we begin</h2>
+                  <p className="text-sm leading-relaxed text-amber-900/80 mb-5">
                     The Confidence Engine helps build confidence by understanding situations before deciding what to do.
                   </p>
-                  <p className="text-sm leading-relaxed text-gray-700 mb-3">
+                  <p className="text-sm leading-relaxed text-amber-900/70 mb-4">
                     You do not need to know exactly what the problem is.
                   </p>
-                  <p className="text-sm leading-relaxed text-gray-700 mb-6">
+                  <p className="text-sm leading-relaxed text-amber-900/70 mb-7">
                     Simply describe what you have observed. We will work through it together, one question at a time.
                   </p>
-                  <div className="flex items-center gap-2 pt-4 border-t border-gray-200">
+                  <div className="flex items-center gap-2 pt-5 border-t border-amber-100/60">
                     <input
                       type="checkbox"
                       id="dismiss-facilitator"
@@ -428,7 +428,7 @@ export default function ScenarioForm() {
 
             {/* Right panel — Workspace (2/3 on desktop) */}
             <div className={hideFacilitatorOnLanding ? "md:col-span-3" : "md:col-span-2"}>
-              <h2 className="mb-3 text-sm font-semibold tracking-wide text-gray-500 uppercase">Tell me what's happening</h2>
+              <h2 className="mb-4 text-xs font-bold tracking-widest uppercase text-gray-400">Tell me what's happening</h2>
               <textarea
                 ref={textareaRef}
                 value={scenario}
@@ -458,8 +458,8 @@ export default function ScenarioForm() {
       )}
 
       {status === "idle" && MOCK_ENABLED && (
-        <details className="rounded-lg border border-gray-200 bg-gray-50">
-          <summary className="cursor-pointer px-4 py-2 text-sm font-medium text-gray-600">Developer details</summary>
+        <details className="rounded-lg border border-gray-200/60 bg-gray-50/30">
+          <summary className="cursor-pointer px-4 py-2 text-sm font-medium text-gray-400 hover:text-gray-600">Developer details</summary>
           <div className="space-y-3 px-4 pb-4">
             <div>
               <label htmlFor="mock-scenario" className="block text-xs font-medium text-gray-500 mb-1">Mock scenario</label>
@@ -483,7 +483,7 @@ export default function ScenarioForm() {
                     type="button"
                     onClick={() => handleScenarioFill(s.key)}
                     disabled={!scenario.trim() && scenario !== s.centralStatement}
-                    className="rounded-md border border-gray-200 bg-white px-3 py-1.5 text-xs text-gray-600 hover:bg-gray-100 disabled:opacity-30"
+                    className="rounded-md border border-gray-200/60 bg-white/80 px-3 py-1.5 text-xs text-gray-500 hover:bg-gray-50 disabled:opacity-30"
                   >
                     {s.label} ({s.turnCount} turns)
                   </button>
@@ -558,7 +558,7 @@ export default function ScenarioForm() {
               setCurrentUnderstanding(null);
               setUpdateError(null);
             }}
-            className="rounded-lg border border-gray-300 px-4 py-2 text-sm font-medium text-gray-600 transition hover:bg-gray-50"
+            className="rounded-lg border border-gray-200/60 px-4 py-2 text-sm font-medium text-gray-500 transition hover:bg-gray-50/80"
           >
             Start new investigation
           </button>
diff --git a/docs/design-evolution-log.md b/docs/design-evolution-log.md
index 28b77a8..50d56d9 100644
--- a/docs/design-evolution-log.md
+++ b/docs/design-evolution-log.md
@@ -293,6 +293,33 @@ Questions
 - Does "Don't show again" feel preferable to automatically hiding the introduction?
 - Should the facilitator panel become an optional workspace companion rather than mandatory onboarding?
 
+Status:
+Completed.
+
+Findings:
+
+- A horizontal facilitator/workspace arrangement feels more natural than stacked onboarding.
+- The workspace becomes the visual destination rather than the introduction.
+- User-controlled dismissal is preferable to automatic hiding.
+- The facilitator feels useful but visually too passive.
+- Remaining issues are now visual hierarchy rather than layout architecture.
+
+### Experiment 06 — Focused Investigation
+
+Hypothesis
+
+The interface should gently guide attention towards the current task without hiding supporting information.
+
+Reducing competition between panels may improve concentration more than introducing additional colour or decoration.
+
+Questions
+
+- Does visual emphasis naturally guide the eye?
+- Can supporting panels become quieter without disappearing?
+- Does the investigation question become the obvious focal point?
+- Does the workspace feel calmer?
+- Are we approaching a professional investigation environment?
+
 Status:
 Experimental.
 
@@ -318,3 +345,11 @@ The "Don't show this introduction again" checkbox uses sessionStorage as a place
 This preference should eventually be handled through user preferences or settings rather than local component state.
 
 TODO: When user accounts are introduced, persist this preference to the user profile so it travels across devices and sessions.
+
+## Future Note — Dark Mode
+
+Dark mode is intentionally deferred.
+
+Once the information architecture and visual hierarchy stabilise we will investigate whether an "Investigation Mode" (rather than a conventional dark mode) improves concentration.
+
+This should be treated as a future UX experiment rather than an accessibility feature.