diff --git a/frontend/src/components/ConfirmDialog.tsx b/frontend/src/components/ConfirmDialog.tsx
index da36019..96dcf6e 100644
--- a/frontend/src/components/ConfirmDialog.tsx
+++ b/frontend/src/components/ConfirmDialog.tsx
@@ -25,7 +25,7 @@ export function ConfirmDialog({
       className="fixed inset-0 z-50 flex items-center justify-center"
     >
       <div className="modal-backdrop absolute inset-0" onClick={onCancel} aria-hidden="true" />
-      <div className="relative card-product shadow-floating max-w-sm w-full mx-md flex flex-col gap-md">
+      <div className="relative card-product max-w-sm w-full mx-md flex flex-col gap-md">
         <h2 id="confirm-dialog-title" className="text-[20px] font-medium text-ink">
           {title}
         </h2>
diff --git a/frontend/src/components/EmptyState.tsx b/frontend/src/components/EmptyState.tsx
index c744642..9725215 100644
--- a/frontend/src/components/EmptyState.tsx
+++ b/frontend/src/components/EmptyState.tsx
@@ -10,7 +10,7 @@ export function EmptyState({ title, description, action }: EmptyStateProps): JSX
   return (
     <div
       data-testid="empty-state"
-      className="card-product flex flex-col items-start gap-md border border-hairline"
+      className="card-product flex flex-col items-start gap-md"
     >
       <h2 className="text-[24px] font-medium text-ink">{title}</h2>
       {description ? <p className="text-[16px] text-charcoal">{description}</p> : null}
diff --git a/frontend/src/components/ErrorState.tsx b/frontend/src/components/ErrorState.tsx
index 20398d7..9bf984b 100644
--- a/frontend/src/components/ErrorState.tsx
+++ b/frontend/src/components/ErrorState.tsx
@@ -9,7 +9,7 @@ export function ErrorState({ title = 'Something went wrong', message, onRetry }:
     <div
       role="alert"
       data-testid="error-state"
-      className="card-product border border-bloom-deep/20 flex flex-col items-start gap-md"
+      className="card-product border-l-4 border-l-bloom-deep flex flex-col items-start gap-md"
     >
       <h2 className="text-[24px] font-medium text-bloom-deep">{title}</h2>
       <p className="text-[16px] text-charcoal">{message}</p>
diff --git a/frontend/src/components/ExportEngagementButton.tsx b/frontend/src/components/ExportEngagementButton.tsx
index 9eecfb4..482cf21 100644
--- a/frontend/src/components/ExportEngagementButton.tsx
+++ b/frontend/src/components/ExportEngagementButton.tsx
@@ -54,7 +54,7 @@ export function ExportEngagementButton({ engagementId }: ExportEngagementButtonP
       <div className="inline-flex">
         <button
           type="button"
-          className="btn-outline rounded-r-none border-r-0"
+          className="btn-outline border-r-0"
           onClick={() => setOpen((v) => !v)}
           data-testid="export-btn"
         >
@@ -64,7 +64,7 @@ export function ExportEngagementButton({ engagementId }: ExportEngagementButtonP
           type="button"
           aria-label="Export options"
           aria-expanded={open}
-          className="btn-outline rounded-l-none px-sm"
+          className="btn-outline px-sm"
           onClick={() => setOpen((v) => !v)}
           data-testid="export-dropdown-toggle"
         >
@@ -74,7 +74,7 @@ export function ExportEngagementButton({ engagementId }: ExportEngagementButtonP
 
       {open ? (
         <div
-          className="absolute right-0 top-full mt-xxs bg-canvas border border-hairline rounded-md shadow-floating dark:shadow-floating-dark z-20 min-w-[160px]"
+          className="absolute right-0 top-full mt-xxs bg-canvas border border-hairline rounded-none z-20 min-w-[160px]"
           role="menu"
         >
           {FORMATS.map(({ label, value }) => (
diff --git a/frontend/src/components/Layout.tsx b/frontend/src/components/Layout.tsx
index e12c4a7..04079ff 100644
--- a/frontend/src/components/Layout.tsx
+++ b/frontend/src/components/Layout.tsx
@@ -34,15 +34,15 @@ export function Layout(): JSX.Element {
           <span className="font-medium tracking-[0.5px] uppercase">Mimic · Purple Team BAS</span>
           {user ? (
             <div className="flex items-center gap-md">
-              <span className="text-[12px] uppercase tracking-[0.5px] text-slab-muted">
+              <span className="text-[12px] uppercase tracking-[0.5px] text-slab-muted font-mono">
                 {user.role}
               </span>
-              <span className="text-[14px]">{user.username}</span>
+              <span className="text-[14px] font-mono">{user.username}</span>
               <button
                 type="button"
                 onClick={cycleTheme}
                 aria-label={`Theme: ${themeLabel(theme)} — click to cycle`}
-                className="flex items-center gap-xxs text-[12px] text-slab-muted hover:text-slab-text transition-colors"
+                className="flex items-center gap-xxs text-[12px] text-slab-muted hover:text-slab-text"
               >
                 <ThemeIcon theme={theme} />
                 <span className="uppercase tracking-[0.5px]">{themeLabel(theme)}</span>
diff --git a/frontend/src/components/LoadingState.tsx b/frontend/src/components/LoadingState.tsx
index 5ce3530..268b7b0 100644
--- a/frontend/src/components/LoadingState.tsx
+++ b/frontend/src/components/LoadingState.tsx
@@ -4,9 +4,9 @@ export function LoadingState({ label = 'Loading…' }: { label?: string }): JSX.
       role="status"
       aria-live="polite"
       data-testid="loading-state"
-      className="flex items-center justify-center py-section text-graphite text-[16px]"
+      className="flex items-center justify-center py-section text-graphite text-[16px] font-mono"
     >
-      <span className="inline-block h-2 w-2 rounded-pill bg-primary animate-pulse mr-sm" />
+      <span className="inline-block h-2 w-2 bg-primary animate-pulse mr-sm" />
       {label}
     </div>
   );
diff --git a/frontend/src/components/MitreMatrixModal.tsx b/frontend/src/components/MitreMatrixModal.tsx
index 88660d0..086058f 100644
--- a/frontend/src/components/MitreMatrixModal.tsx
+++ b/frontend/src/components/MitreMatrixModal.tsx
@@ -170,7 +170,7 @@ export function MitreMatrixModal({
         role="dialog"
         aria-modal="true"
         aria-labelledby="matrix-modal-title"
-        className="relative bg-canvas rounded-xl shadow-floating dark:shadow-floating-dark max-w-[98vw] max-h-[80vh] overflow-hidden flex flex-col"
+        className="relative bg-canvas rounded-none border border-hairline max-w-[98vw] max-h-[80vh] overflow-hidden flex flex-col"
         style={{ width: '1400px' }}
         onKeyDown={handleKeyDown}
       >
@@ -230,7 +230,7 @@ export function MitreMatrixModal({
                       type="button"
                       onClick={() => toggleTactic(tactic.tactic_id)}
                       title={`${tactic.tactic_name} (${tactic.tactic_id}) — click to tag this tactic`}
-                      className={`w-full text-left px-xs py-xxs rounded-t-sm border border-b-0 border-hairline transition-colors ${
+                      className={`w-full text-left px-xs py-xxs rounded-none border border-b-0 border-hairline ${
                         tacticSelected
                           ? 'bg-primary border-primary'
                           : 'bg-cloud hover:bg-fog'
@@ -251,7 +251,7 @@ export function MitreMatrixModal({
                     </button>
 
                     {/* Techniques */}
-                    <div className="border border-hairline rounded-b-sm overflow-hidden flex flex-col">
+                    <div className="border border-hairline rounded-none overflow-hidden flex flex-col">
                       {visibleTechniques.map((tech, techIdx) => {
                         const isSelected = selectedTechMap.has(tech.id);
                         const isExpanded = expandedTechniques.has(tech.id) || autoExpanded.has(tech.id);
@@ -296,7 +296,7 @@ export function MitreMatrixModal({
                                   isSelected ? 'text-white' : 'text-ink'
                                 }`}
                               >
-                                <span className="font-semibold block truncate">{tech.id}</span>
+                                <span className="font-mono font-semibold block truncate">{tech.id}</span>
                                 <span className={`block truncate text-[10px] ${isSelected ? 'text-white/80' : 'text-charcoal'}`}>
                                   {tech.name}
                                 </span>
@@ -318,7 +318,7 @@ export function MitreMatrixModal({
                                         : 'bg-cloud text-charcoal hover:bg-fog'
                                     }`}
                                   >
-                                    <span className="font-semibold block truncate">{sub.id}</span>
+                                    <span className="font-mono font-semibold block truncate">{sub.id}</span>
                                     <span className="block truncate">{sub.name}</span>
                                   </button>
                                 );
diff --git a/frontend/src/components/MitreTechniquePicker.tsx b/frontend/src/components/MitreTechniquePicker.tsx
index 5d0106b..1190881 100644
--- a/frontend/src/components/MitreTechniquePicker.tsx
+++ b/frontend/src/components/MitreTechniquePicker.tsx
@@ -107,7 +107,7 @@ export function MitreTechniquePicker({
       />
 
       {open && (
-        <div className="absolute z-20 w-full mt-xxs bg-canvas border border-steel rounded-md shadow-floating overflow-hidden">
+        <div className="absolute z-20 w-full mt-xxs bg-canvas border border-steel rounded-none overflow-hidden">
           {isFetching && (
             <div className="px-md py-sm text-[14px] text-graphite">Searching…</div>
           )}
@@ -144,10 +144,10 @@ export function MitreTechniquePicker({
                     selectItem(item);
                   }}
                 >
-                  <span className="font-medium">{item.id}</span>
+                  <span className="font-mono font-medium">{item.id}</span>
                   <span className="text-charcoal"> — {item.name}</span>
                   {item.tactics.length > 0 && (
-                    <span className="text-graphite"> ({item.tactics[0]})</span>
+                    <span className="font-mono text-graphite"> ({item.tactics[0]})</span>
                   )}
                 </li>
               ))}
diff --git a/frontend/src/components/MitreTechniqueTag.tsx b/frontend/src/components/MitreTechniqueTag.tsx
index 7874057..a064d1f 100644
--- a/frontend/src/components/MitreTechniqueTag.tsx
+++ b/frontend/src/components/MitreTechniqueTag.tsx
@@ -12,7 +12,7 @@ interface TacticTagProps {
   disabled?: boolean;
 }
 
-// Technique chip — soft blue, id only, name in title
+// Technique tag — angular, soft blue, monospace ID
 export function MitreTechniqueTag({
   technique,
   onRemove,
@@ -22,7 +22,7 @@ export function MitreTechniqueTag({
     <span
       data-testid="mitre-technique-tag"
       title={`${technique.id} — ${technique.name}`}
-      className="inline-flex items-center gap-xxs bg-primary-soft text-primary-deep rounded-full px-sm py-xxs text-[13px] font-medium"
+      className="inline-flex items-center gap-xxs bg-primary-soft text-primary-deep rounded-none border border-primary-soft px-sm py-xxs text-[13px] font-mono"
     >
       {technique.id}
       {!disabled && (
@@ -39,7 +39,7 @@ export function MitreTechniqueTag({
   );
 }
 
-// Tactic chip — primary blue filled, id only, name in title
+// Tactic tag — angular, primary blue filled, monospace ID
 export function MitreTacticTag({
   tactic,
   onRemove,
@@ -49,7 +49,7 @@ export function MitreTacticTag({
     <span
       data-testid="mitre-tactic-tag"
       title={`${tactic.id} — ${tactic.name}`}
-      className="inline-flex items-center gap-xxs bg-primary text-white rounded-full px-sm py-xxs text-[13px] font-medium"
+      className="inline-flex items-center gap-xxs bg-primary text-white rounded-none px-sm py-xxs text-[13px] font-mono"
     >
       {tactic.id}
       {!disabled && (
diff --git a/frontend/src/components/MitreTechniquesField.tsx b/frontend/src/components/MitreTechniquesField.tsx
index 1c1cc09..6314bd8 100644
--- a/frontend/src/components/MitreTechniquesField.tsx
+++ b/frontend/src/components/MitreTechniquesField.tsx
@@ -116,7 +116,7 @@ export function MitreTechniquesField({
             aria-label="Open MITRE matrix"
             onClick={() => { setShowPicker(false); setShowMatrix(true); }}
             disabled={isPending}
-            className="flex-shrink-0 flex items-center justify-center w-9 h-9 rounded-md border border-steel text-graphite hover:text-ink hover:border-ink transition-colors"
+            className="flex-shrink-0 flex items-center justify-center w-9 h-9 rounded-none border border-steel text-graphite hover:text-ink hover:border-ink"
           >
             <Grid2x2 size={16} />
           </button>
diff --git a/frontend/src/components/SimulationList.tsx b/frontend/src/components/SimulationList.tsx
index 2028e9d..6d301d8 100644
--- a/frontend/src/components/SimulationList.tsx
+++ b/frontend/src/components/SimulationList.tsx
@@ -73,7 +73,7 @@ function NewSimulationDropdown({ engagementId }: { engagementId: number }): JSX.
       <div className="inline-flex">
         <button
           type="button"
-          className="btn-primary rounded-r-none border-r border-primary-deep"
+          className="btn-primary border-r border-primary-deep"
           onClick={handleBlank}
           data-testid="new-simulation-btn"
         >
@@ -83,7 +83,7 @@ function NewSimulationDropdown({ engagementId }: { engagementId: number }): JSX.
           type="button"
           aria-label="More options"
           aria-expanded={open}
-          className="btn-primary rounded-l-none px-sm"
+          className="btn-primary px-sm"
           onClick={() => setOpen((v) => !v)}
           data-testid="new-simulation-dropdown-toggle"
         >
@@ -93,7 +93,7 @@ function NewSimulationDropdown({ engagementId }: { engagementId: number }): JSX.
 
       {open ? (
         <div
-          className="absolute right-0 top-full mt-xxs bg-canvas border border-hairline rounded-md shadow-floating dark:shadow-floating-dark z-20 min-w-[180px]"
+          className="absolute right-0 top-full mt-xxs bg-canvas border border-hairline rounded-none z-20 min-w-[180px]"
           role="menu"
         >
           <button
@@ -199,7 +199,7 @@ export function SimulationList({ engagementId }: SimulationListProps): JSX.Eleme
                     {sim.name}
                   </Link>
                 </td>
-                <td className="px-xl py-md text-charcoal text-[14px]">
+                <td className="px-xl py-md text-charcoal text-[14px] font-mono">
                   {(() => {
                     const items = [
                       ...(sim.tactics ?? []).map((t) => t.id),
@@ -213,7 +213,7 @@ export function SimulationList({ engagementId }: SimulationListProps): JSX.Eleme
                 <td className="px-xl py-md">
                   <SimulationStatusBadge status={sim.status} />
                 </td>
-                <td className="px-xl py-md text-charcoal text-[14px]">
+                <td className="px-xl py-md text-charcoal text-[14px] font-mono">
                   {formatDate(sim.executed_at)}
                 </td>
               </tr>
diff --git a/frontend/src/components/SimulationStatusBadge.tsx b/frontend/src/components/SimulationStatusBadge.tsx
index 7d8cf78..7665441 100644
--- a/frontend/src/components/SimulationStatusBadge.tsx
+++ b/frontend/src/components/SimulationStatusBadge.tsx
@@ -7,19 +7,17 @@ const LABELS: Record<SimulationStatus, string> = {
   done: 'Done',
 };
 
-// Fixed colors — badge backgrounds are decorative/semantic, not themeable.
-// text-white is hardcoded (not text-canvas) so dark mode doesn't invert it to near-black.
 const STYLES: Record<SimulationStatus, string> = {
-  pending: 'bg-fog text-charcoal border border-hairline',
+  pending: 'bg-cloud text-graphite border border-hairline',
   in_progress: 'bg-primary-soft text-primary-deep',
-  review_required: 'bg-bloom-coral text-white',
-  done: 'bg-storm-deep text-white',
+  review_required: 'bg-warn-soft text-warn',
+  done: 'bg-success-soft text-success',
 };
 
 export function SimulationStatusBadge({ status }: { status: SimulationStatus }): JSX.Element {
   return (
     <span
-      className={`inline-flex items-center rounded-lg px-3 py-[6px] text-[14px] leading-[1.3] font-medium ${STYLES[status]}`}
+      className={`inline-flex items-center rounded-pill px-3 py-[6px] text-[14px] leading-[1.3] font-medium ${STYLES[status]}`}
       data-testid="simulation-status-badge"
       data-status={status}
     >
diff --git a/frontend/src/components/StatusBadge.tsx b/frontend/src/components/StatusBadge.tsx
index 74290f0..971f7ec 100644
--- a/frontend/src/components/StatusBadge.tsx
+++ b/frontend/src/components/StatusBadge.tsx
@@ -7,17 +7,15 @@ const LABELS: Record<EngagementStatus, string> = {
 };
 
 const STYLES: Record<EngagementStatus, string> = {
-  // Outlined ink for planned (neutral), filled primary for active (engagement live),
-  // outlined steel for closed (muted). Stays within DESIGN.md palette.
-  planned: 'bg-canvas text-ink border border-ink',
-  active: 'bg-primary text-white',
+  planned: 'bg-warn-soft text-warn border border-warn',
+  active: 'bg-primary-soft text-primary-deep',
   closed: 'bg-cloud text-graphite border border-hairline',
 };
 
 export function StatusBadge({ status }: { status: EngagementStatus }): JSX.Element {
   return (
     <span
-      className={`inline-flex items-center rounded-lg px-3 py-[6px] text-[14px] leading-[1.3] font-medium ${STYLES[status]}`}
+      className={`inline-flex items-center rounded-pill px-3 py-[6px] text-[14px] leading-[1.3] font-medium ${STYLES[status]}`}
       data-testid="status-badge"
       data-status={status}
     >
diff --git a/frontend/src/components/TemplatePickerModal.tsx b/frontend/src/components/TemplatePickerModal.tsx
index ccb16a9..4ca9452 100644
--- a/frontend/src/components/TemplatePickerModal.tsx
+++ b/frontend/src/components/TemplatePickerModal.tsx
@@ -34,7 +34,7 @@ export function TemplatePickerModal({
     >
       <div className="modal-backdrop absolute inset-0" onClick={onClose} aria-hidden="true" />
 
-      <div className="relative card-product shadow-floating dark:shadow-floating-dark max-w-xl w-full mx-md flex flex-col gap-md max-h-[80vh] overflow-hidden">
+      <div className="relative card-product max-w-xl w-full mx-md flex flex-col gap-md max-h-[80vh] overflow-hidden">
         <div className="flex items-center justify-between">
           <h2 id="tpl-picker-title" className="text-[20px] font-medium text-ink">
             From template…
@@ -43,7 +43,7 @@ export function TemplatePickerModal({
             type="button"
             aria-label="Close"
             onClick={onClose}
-            className="text-graphite hover:text-ink transition-colors text-[20px] leading-none"
+            className="text-graphite hover:text-ink text-[20px] leading-none"
           >
             ×
           </button>
diff --git a/frontend/src/components/Toast.tsx b/frontend/src/components/Toast.tsx
index 0e267b8..3e0ed7e 100644
--- a/frontend/src/components/Toast.tsx
+++ b/frontend/src/components/Toast.tsx
@@ -1,9 +1,5 @@
 import { useToast } from '@/hooks/useToast';
 
-/**
- * Stack of toast notifications anchored bottom-right.
- * Pure DESIGN.md surfaces: rounded-xl, soft-lift, ink slab for errors.
- */
 export function ToastViewport(): JSX.Element {
   const { toasts, dismiss } = useToast();
   return (
@@ -15,19 +11,18 @@ export function ToastViewport(): JSX.Element {
       {toasts.map((t) => {
         const isError = t.kind === 'error';
         const isSuccess = t.kind === 'success';
-        // Fixed colors: toasts don't theme (error=dark slab, success=primary blue)
         const surface = isError
-          ? 'bg-slab text-slab-text'
+          ? 'bg-paper text-ink border border-hairline border-l-4 border-l-bloom-deep'
           : isSuccess
-            ? 'bg-primary text-white'
-            : 'bg-canvas text-ink border border-hairline';
+            ? 'bg-paper text-ink border border-hairline border-l-4 border-l-success'
+            : 'bg-paper text-ink border border-hairline border-l-4 border-l-primary';
         return (
           <div
             key={t.id}
             role="status"
             data-testid="toast"
             data-kind={t.kind}
-            className={`pointer-events-auto rounded-xl px-md py-sm shadow-soft-lift text-[14px] leading-[1.4] ${surface}`}
+            className={`pointer-events-auto rounded-none px-md py-sm text-[14px] leading-[1.4] ${surface}`}
           >
             <div className="flex items-start justify-between gap-sm">
               <span className="flex-1">{t.message}</span>