diff --git a/design-system/documentation/token-catalog.md b/design-system/documentation/token-catalog.md
index 5aa761e..9316401 100644
--- a/design-system/documentation/token-catalog.md
+++ b/design-system/documentation/token-catalog.md
@@ -14,7 +14,7 @@ components to the design system.
 | Borders and radius | `tokens/borders.json` | `--radius-*`, `--border-width-*`, `--border-default`, `--border-subtle`, `--border-emphasis`, `--border-interactive`, `--border-error`, `--border-success` | `Field`, `VaultCard`, `ConfirmationModal`, wallet dropdowns, pills, avatars, focus states |
 | Shadows | `tokens/shadows.json` | Elevation references for raised surfaces and overlays | Modals, dropdowns, raised cards, dashboard surfaces |
 | Motion | `tokens/motion.json` | `src/utils/motion.ts` exports `duration`, `ease`, `transitionEnter`, `transitionExit`, and `transitionPage` | `Notification`, animated overlays, dropdowns, page transitions |
-| Z-index | `tokens/z-index.json` | `--z-index-base`, `--z-index-header`, `--z-index-drawer`, `--z-index-modal`, `--z-index-toast` | `Layout`, `MobileDrawer`, `ConfirmationModal`, wallet modals, notification popovers |
+| Z-index | `tokens/z-index.json` | `--z-index-base`, `--z-index-header`, `--z-index-drawer`, `--z-index-modal`, `--z-index-toast` | `Layout`, `MobileDrawer`, `ConfirmationModal`, wallet modals, notification popovers |`n| Opacity | `tokens/opacity.json` | `--opacity-disabled`, `--opacity-backdrop`, `--opacity-hover`, `--opacity-muted` | `Field`, `Modal`, disabled controls, overlays |
 
 ## Component Notes
 
diff --git a/design-system/src/__tests__/token-loader.test.ts b/design-system/src/__tests__/token-loader.test.ts
index b67e0dd..d9ed795 100644
--- a/design-system/src/__tests__/token-loader.test.ts
+++ b/design-system/src/__tests__/token-loader.test.ts
@@ -25,140 +25,147 @@ describe('token-loader', () => {
     });
 
     it('should throw if JSON is malformed', () => {
-        mockedFs.readFileSync.mockReturnValue('{"invalid": }');
-        expect(() => loadTokens('invalid.json')).toThrow();
+      mockedFs.readFileSync.mockReturnValue('{"invalid": }');
+      expect(() => loadTokens('invalid.json')).toThrow();
     });
   });
 
   describe('getAllTokens', () => {
     it('should merge all tokens', () => {
-        mockedFs.readFileSync.mockImplementation((path) => {
-            if (path.toString().includes('colors.json')) return '{"color": "red"}';
-            if (path.toString().includes('typography.json')) return '{"font": "sans"}';
-            if (path.toString().includes('spacing.json')) return '{"space": "4px"}';
-            if (path.toString().includes('shadows.json')) return '{"shadow": "1px"}';
-            if (path.toString().includes('motion.json')) return '{"motion": "ease"}';
-            if (path.toString().includes('borders.json')) return '{"border": "1px"}';
-            return '{}';
-        });
-
-        const allTokens = getAllTokens();
-        expect(allTokens).toEqual({
-            "color": "red",
-            "font": "sans",
-            "space": "4px",
-            "shadow": "1px",
-            "motion": "ease",
-            "border": "1px"
-        });
+      mockedFs.readFileSync.mockImplementation((path) => {
+        if (path.toString().includes('colors.json')) return '{"color": "red"}';
+        if (path.toString().includes('typography.json')) return '{"font": "sans"}';
+        if (path.toString().includes('spacing.json')) return '{"space": "4px"}';
+        if (path.toString().includes('shadows.json')) return '{"shadow": "1px"}';
+        if (path.toString().includes('motion.json')) return '{"motion": "ease"}';
+        if (path.toString().includes('borders.json')) return '{"border": "1px"}';
+        if (path.toString().includes('z-index.json')) return '{"zIndex": 100}';
+        if (path.toString().includes('opacity.json')) return '{"opacity": 0.5}';
+        return '{}';
+      });
+
+      const allTokens = getAllTokens();
+      expect(allTokens).toEqual({
+        "color": "red",
+        "font": "sans",
+        "space": "4px",
+        "shadow": "1px",
+        "motion": "ease",
+        "border": "1px",
+        "zIndex": 100,
+        "opacity": 0.5
+      });
     });
 
     it('should continue and warn if a file fails to load', () => {
-        mockedFs.readFileSync.mockImplementation((path) => {
-            if (path.toString().includes('typography.json')) throw new Error('File not found');
-            if (path.toString().includes('colors.json')) return '{"color": "red"}';
-            if (path.toString().includes('spacing.json')) return '{"space": "4px"}';
-            if (path.toString().includes('shadows.json')) return '{"shadow": "1px"}';
-            if (path.toString().includes('motion.json')) return '{"motion": "ease"}';
-            if (path.toString().includes('borders.json')) return '{"border": "1px"}';
-            return '{}';
-        });
-
-        const allTokens = getAllTokens();
-
-        // The failed file is omitted, every other file is still merged.
-        expect(allTokens).toEqual({
-            "color": "red",
-            "space": "4px",
-            "shadow": "1px",
-            "motion": "ease",
-            "border": "1px"
-        });
-        expect(allTokens).not.toHaveProperty('font');
+      mockedFs.readFileSync.mockImplementation((path) => {
+        if (path.toString().includes('typography.json')) throw new Error('File not found');
+        if (path.toString().includes('colors.json')) return '{"color": "red"}';
+        if (path.toString().includes('spacing.json')) return '{"space": "4px"}';
+        if (path.toString().includes('shadows.json')) return '{"shadow": "1px"}';
+        if (path.toString().includes('motion.json')) return '{"motion": "ease"}';
+        if (path.toString().includes('borders.json')) return '{"border": "1px"}';
+        if (path.toString().includes('z-index.json')) return '{"zIndex": 100}';
+        if (path.toString().includes('opacity.json')) return '{"opacity": 0.5}';
+        return '{}';
+      });
+
+      const allTokens = getAllTokens();
+
+      expect(allTokens).toEqual({
+        "color": "red",
+        "space": "4px",
+        "shadow": "1px",
+        "motion": "ease",
+        "border": "1px",
+        "zIndex": 100,
+        "opacity": 0.5
+      });
+      expect(allTokens).not.toHaveProperty('font');
     });
 
     it('should warn with the name of the file that failed to load', () => {
-        mockedFs.readFileSync.mockImplementation((path) => {
-            if (path.toString().includes('typography.json')) throw new Error('File not found');
-            return '{}';
-        });
-
-        getAllTokens();
-
-        expect(console.warn).toHaveBeenCalledTimes(1);
-        expect(console.warn).toHaveBeenCalledWith(
-            'Failed to load typography.json:',
-            expect.any(Error)
-        );
+      mockedFs.readFileSync.mockImplementation((path) => {
+        if (path.toString().includes('typography.json')) throw new Error('File not found');
+        return '{}';
+      });
+
+      getAllTokens();
+
+      expect(console.warn).toHaveBeenCalledTimes(1);
+      expect(console.warn).toHaveBeenCalledWith(
+        'Failed to load typography.json:',
+        expect.any(Error)
+      );
     });
-    
+
     it('should continue and warn if a file has malformed JSON', () => {
-        mockedFs.readFileSync.mockImplementation((path) => {
-            if (path.toString().includes('typography.json')) return '{"invalid": }';
-            if (path.toString().includes('colors.json')) return '{"color": "red"}';
-            if (path.toString().includes('spacing.json')) return '{"space": "4px"}';
-            if (path.toString().includes('shadows.json')) return '{"shadow": "1px"}';
-            if (path.toString().includes('motion.json')) return '{"motion": "ease"}';
-            if (path.toString().includes('borders.json')) return '{"border": "1px"}';
-            return '{}';
-        });
-
-        const allTokens = getAllTokens();
-
-        // A parse error is caught just like a read error: the bad file is dropped.
-        expect(allTokens).toEqual({
-            "color": "red",
-            "space": "4px",
-            "shadow": "1px",
-            "motion": "ease",
-            "border": "1px"
-        });
-        expect(console.warn).toHaveBeenCalledWith(
-            'Failed to load typography.json:',
-            expect.any(SyntaxError)
-        );
+      mockedFs.readFileSync.mockImplementation((path) => {
+        if (path.toString().includes('typography.json')) return '{"invalid": }';
+        if (path.toString().includes('colors.json')) return '{"color": "red"}';
+        if (path.toString().includes('spacing.json')) return '{"space": "4px"}';
+        if (path.toString().includes('shadows.json')) return '{"shadow": "1px"}';
+        if (path.toString().includes('motion.json')) return '{"motion": "ease"}';
+        if (path.toString().includes('borders.json')) return '{"border": "1px"}';
+        if (path.toString().includes('z-index.json')) return '{"zIndex": 100}';
+        if (path.toString().includes('opacity.json')) return '{"opacity": 0.5}';
+        return '{}';
+      });
+
+      const allTokens = getAllTokens();
+
+      expect(allTokens).toEqual({
+        "color": "red",
+        "space": "4px",
+        "shadow": "1px",
+        "motion": "ease",
+        "border": "1px",
+        "zIndex": 100,
+        "opacity": 0.5
+      });
+      expect(console.warn).toHaveBeenCalledWith(
+        'Failed to load typography.json:',
+        expect.any(SyntaxError)
+      );
     });
 
     it('should let later files override earlier keys via Object.assign', () => {
-        // colors.json is merged first, borders.json last; the shared "token"
-        // key must reflect the last file processed.
-        mockedFs.readFileSync.mockImplementation((path) => {
-            if (path.toString().includes('colors.json')) return '{"token": "from-colors"}';
-            if (path.toString().includes('borders.json')) return '{"token": "from-borders"}';
-            return '{}';
-        });
+      mockedFs.readFileSync.mockImplementation((path) => {
+        if (path.toString().includes('colors.json')) return '{"token": "from-colors"}';
+        if (path.toString().includes('opacity.json')) return '{"token": "from-opacity"}';
+        return '{}';
+      });
 
-        const allTokens = getAllTokens();
+      const allTokens = getAllTokens();
 
-        expect(allTokens).toEqual({"token": "from-borders"});
+      expect(allTokens).toEqual({"token": "from-opacity"});
     });
 
     it('should still merge a file ordered after a failing one', () => {
-        mockedFs.readFileSync.mockImplementation((path) => {
-            // colors (first) fails, borders (last) must still be merged.
-            if (path.toString().includes('colors.json')) throw new Error('File not found');
-            if (path.toString().includes('borders.json')) return '{"border": "1px"}';
-            return '{}';
-        });
-
-        const allTokens = getAllTokens();
-
-        expect(allTokens).toEqual({"border": "1px"});
-        expect(console.warn).toHaveBeenCalledWith(
-            'Failed to load colors.json:',
-            expect.any(Error)
-        );
+      mockedFs.readFileSync.mockImplementation((path) => {
+        if (path.toString().includes('colors.json')) throw new Error('File not found');
+        if (path.toString().includes('opacity.json')) return '{"opacity": 0.5}';
+        return '{}';
+      });
+
+      const allTokens = getAllTokens();
+
+      expect(allTokens).toEqual({"opacity": 0.5});
+      expect(console.warn).toHaveBeenCalledWith(
+        'Failed to load colors.json:',
+        expect.any(Error)
+      );
     });
 
     it('should return an empty object and warn once per file when all files fail', () => {
-        mockedFs.readFileSync.mockImplementation(() => {
-            throw new Error('File not found');
-        });
+      mockedFs.readFileSync.mockImplementation(() => {
+        throw new Error('File not found');
+      });
 
-        const allTokens = getAllTokens();
+      const allTokens = getAllTokens();
 
-        expect(allTokens).toEqual({});
-        expect(console.warn).toHaveBeenCalledTimes(7);
+      expect(allTokens).toEqual({});
+      expect(console.warn).toHaveBeenCalledTimes(8);
     });
   });
-});
+});
\ No newline at end of file
diff --git a/design-system/src/__tests__/tokens.test.ts b/design-system/src/__tests__/tokens.test.ts
index 8c898d6..9210cbe 100644
--- a/design-system/src/__tests__/tokens.test.ts
+++ b/design-system/src/__tests__/tokens.test.ts
@@ -28,3 +28,17 @@ describe('z-index token layering scale', () => {
     });
   });
 });
+
+describe('opacity token scale', () => {
+  it('loads opacity tokens from opacity.json', () => {
+    const tokens = loadTokens('opacity.json');
+
+    expect(tokens).toHaveProperty('opacity');
+    expect(tokens.opacity).toMatchObject({
+      disabled: { $value: 0.5 },
+      backdrop: { $value: 0.5 },
+      hover: { $value: 0.08 },
+      muted: { $value: 0.72 },
+    });
+  });
+});
\ No newline at end of file
diff --git a/design-system/src/utils/token-loader.ts b/design-system/src/utils/token-loader.ts
index 8c2f4b0..7b49b1e 100644
--- a/design-system/src/utils/token-loader.ts
+++ b/design-system/src/utils/token-loader.ts
@@ -26,7 +26,7 @@ export function loadTokens(tokenFile: string): DesignTokens {
 }
 
 export function getAllTokens(): DesignTokens {
-  const tokenFiles = ['colors.json', 'typography.json', 'spacing.json', 'shadows.json', 'motion.json', 'borders.json', 'z-index.json'];
+  const tokenFiles = ['colors.json', 'typography.json', 'spacing.json', 'shadows.json', 'motion.json', 'borders.json', 'z-index.json', 'opacity.json'];
   const allTokens: DesignTokens = {};
   
   tokenFiles.forEach(file => {
diff --git a/design-system/tokens/opacity.json b/design-system/tokens/opacity.json
new file mode 100644
index 0000000..cb72e51
--- /dev/null
+++ b/design-system/tokens/opacity.json
@@ -0,0 +1,25 @@
+{
+  "$schema": "https://design-tokens.github.io/community-group/format.json",
+  "opacity": {
+    "disabled": {
+      "$type": "number",
+      "$value": 0.5,
+      "$description": "Disabled control opacity"
+    },
+    "backdrop": {
+      "$type": "number",
+      "$value": 0.5,
+      "$description": "Modal and overlay backdrop opacity"
+    },
+    "hover": {
+      "$type": "number",
+      "$value": 0.08,
+      "$description": "Subtle hover-state layer opacity"
+    },
+    "muted": {
+      "$type": "number",
+      "$value": 0.72,
+      "$description": "Muted content opacity when color alone is not enough"
+    }
+  }
+}
\ No newline at end of file
diff --git a/src/components/Field.tsx b/src/components/Field.tsx
index 6358cba..d347e48 100644
--- a/src/components/Field.tsx
+++ b/src/components/Field.tsx
@@ -8,7 +8,7 @@ interface FieldProps extends Omit<React.InputHTMLAttributes<HTMLInputElement>, '
 }
 
 export const Field = React.forwardRef<HTMLInputElement, FieldProps>(
-  ({ label, hint, error, id, required, ...props }, ref) => {
+  ({ label, hint, error, id, required, disabled, style, ...props }, ref) => {
   const fieldId = id || `field-${label.toLowerCase().replace(/\s+/g, '-')}`
   const errorId = error ? `${fieldId}-error` : undefined
   const hintId = hint && !error ? `${fieldId}-hint` : undefined
@@ -30,6 +30,7 @@ export const Field = React.forwardRef<HTMLInputElement, FieldProps>(
         ref={ref}
         id={fieldId}
         required={required}
+        disabled={disabled}
         aria-label={label}
         aria-describedby={describedBy}
         aria-invalid={error ? 'true' : undefined}
@@ -40,6 +41,9 @@ export const Field = React.forwardRef<HTMLInputElement, FieldProps>(
           border: error ? '1px solid var(--danger)' : '1px solid var(--border)',
           background: 'var(--surface)',
           color: 'var(--text)',
+          opacity: disabled ? 'var(--opacity-disabled)' : undefined,
+          cursor: disabled ? 'not-allowed' : undefined,
+          ...style,
         }}
         {...props}
       />
diff --git a/src/components/Modal.tsx b/src/components/Modal.tsx
index f018c25..d3b1b9c 100644
--- a/src/components/Modal.tsx
+++ b/src/components/Modal.tsx
@@ -18,7 +18,7 @@ export function Modal({
   children,
   ariaLabelledBy,
   ariaDescribedBy,
-  overlayClassName = "fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/50 backdrop-blur-sm",
+  overlayClassName = "fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/[var(--opacity-backdrop)] backdrop-blur-sm",
   contentClassName = "bg-white dark:bg-gray-800 rounded-xl shadow-2xl max-w-lg w-full overflow-hidden flex flex-col",
 }: ModalProps) {
   const shouldReduceMotion = useReducedMotion();
diff --git a/src/index.css b/src/index.css
index 76707f8..384ec8d 100644
--- a/src/index.css
+++ b/src/index.css
@@ -100,6 +100,12 @@
   --z-index-drawer: 200;
   --z-index-modal: 300;
   --z-index-toast: 400;
+
+  /* Opacity scale — mirrors design-system/tokens/opacity.json */
+  --opacity-disabled: 0.5;
+  --opacity-backdrop: 0.5;
+  --opacity-hover: 0.08;
+  --opacity-muted: 0.72;
 }
 
 /* Responsive breakpoints - update CSS variables */