diff --git a/.changeset/activate-shadcn-color-tokens.md b/.changeset/activate-shadcn-color-tokens.md
new file mode 100644
index 0000000000..822bf3d66a
--- /dev/null
+++ b/.changeset/activate-shadcn-color-tokens.md
@@ -0,0 +1,36 @@
+---
+'@accounter/client': patch
+---
+
+Activate the shadcn colour tokens, which have been compiling to nothing since the Tailwind v4
+migration.
+
+`components.json` declared `cssVariables: false` and pointed `tailwind.config.cjs` — a file that does
+not exist anywhere in the monorepo. It was deleted during the v3 → v4 migration and the theme layer
+was never ported to v4's CSS-first `@theme`, so `--color-card`, `--color-muted-foreground`,
+`--color-destructive` and the rest were never registered and Tailwind never generated the utilities
+that reference them. Roughly 380 usages across ~100 files were inert: `text-muted-foreground`,
+`bg-card`, `border-border` and `text-destructive` each emitted **zero** rules into the bundle, so
+secondary text rendered as full-strength body colour, `bg-muted`/`bg-accent`/`bg-card` were
+transparent, and error text rendered black instead of red.
+
+`src/index.css` now defines the full token set in `@theme` on shadcn's `gray` base, with `.dark`
+overrides in `@layer base`. Values are literal `oklch()` rather than `var(--color-gray-500)`
+references, because Tailwind v4 only emits the default palette variables it sees used — referencing
+one that happens to be unused elsewhere would resolve to nothing. Tokens that stood in for an
+existing default were given that default's value, so classes which were previously no-ops stay
+visually unchanged: `--color-background`/`--color-card` are white (already the page background),
+`--color-foreground` is gray-950 (already the inherited text colour), and `--color-border` is gray-200
+to match the `border-color` compatibility rule already in the base layer. The visible changes are the
+genuinely broken cases — muted text now reads gray-500, `text-destructive` reads red-600, and
+`bg-muted`/`bg-accent`/`bg-secondary` gain their light tint.
+
+Also fixes `business/client/charts-section.tsx`, which set its axis ticks with
+`hsl(var(--muted-foreground))`. That is v3 syntax: the v4 token is `--color-muted-foreground` and
+holds a colour rather than an HSL triplet, so the `hsl()` wrapper produced an invalid value and the
+ticks fell back to Recharts' default. Its `hsl(var(--chart-N))` siblings are correct and unchanged —
+the `--chart-*` family really is stored as triplets.
+
+Dark mode remains inert: `next-themes` is installed but no `ThemeProvider` is mounted, so nothing ever
+puts `.dark` on an ancestor. The overrides are defined so the ~425 `dark:` utilities already in the
+codebase are correct when that switch is eventually wired.
diff --git a/packages/client/components.json b/packages/client/components.json
index d940d3dc99..55d11a924e 100644
--- a/packages/client/components.json
+++ b/packages/client/components.json
@@ -4,10 +4,10 @@
   "rsc": false,
   "tsx": true,
   "tailwind": {
-    "config": "tailwind.config.cjs",
+    "config": "",
     "css": "src/index.css",
     "baseColor": "gray",
-    "cssVariables": false,
+    "cssVariables": true,
     "prefix": ""
   },
   "aliases": {
diff --git a/packages/client/src/components/business/client/charts-section.tsx b/packages/client/src/components/business/client/charts-section.tsx
index 26c4da34f2..475d631b47 100644
--- a/packages/client/src/components/business/client/charts-section.tsx
+++ b/packages/client/src/components/business/client/charts-section.tsx
@@ -88,9 +88,9 @@ export function ChartsSection() {
               <XAxis
                 dataKey="month"
                 className="text-xs"
-                tick={{ fill: 'hsl(var(--muted-foreground))' }}
+                tick={{ fill: 'var(--color-muted-foreground)' }}
               />
-              <YAxis className="text-xs" tick={{ fill: 'hsl(var(--muted-foreground))' }} />
+              <YAxis className="text-xs" tick={{ fill: 'var(--color-muted-foreground)' }} />
               <ChartTooltip content={<ChartTooltipContent />} />
               <Line
                 type="monotone"
diff --git a/packages/client/src/index.css b/packages/client/src/index.css
index be8f8d36b4..414d2a8e0c 100644
--- a/packages/client/src/index.css
+++ b/packages/client/src/index.css
@@ -4,7 +4,56 @@
 
 @plugin 'tailwindcss-animate';
 
+/*
+  shadcn/ui colour tokens.
+
+  These were never ported when this project moved from Tailwind v3 (which configured them in a
+  `tailwind.config.cjs` that no longer exists) to v4's CSS-first `@theme`. Until now the token
+  namespace was simply undefined, so every `text-muted-foreground` / `bg-card` / `border-border` /
+  `text-destructive` in the codebase — roughly 380 usages across ~100 files — compiled to no rule at
+  all and rendered as inherited black on transparent.
+
+  Values follow shadcn's `gray` base (see `components.json`) and are written as literal `oklch()`
+  rather than `var(--color-gray-500)` on purpose: Tailwind v4 only emits the default palette
+  variables it sees used, so referencing one that happens to be unused elsewhere would resolve to
+  nothing.
+
+  Plain `@theme`, NOT `@theme inline` — inline substitutes the literal value into each utility, which
+  would make the `.dark` overrides below dead code.
+*/
 @theme {
+  --color-background: #fff;
+  --color-foreground: oklch(13% 0.028 261.692); /* gray-950 */
+
+  --color-card: #fff;
+  --color-card-foreground: oklch(13% 0.028 261.692); /* gray-950 */
+
+  --color-popover: #fff;
+  --color-popover-foreground: oklch(13% 0.028 261.692); /* gray-950 */
+
+  --color-primary: oklch(21% 0.034 264.665); /* gray-900 */
+  --color-primary-foreground: oklch(98.5% 0.002 247.839); /* gray-50 */
+
+  --color-secondary: oklch(96.7% 0.003 264.542); /* gray-100 */
+  --color-secondary-foreground: oklch(21% 0.034 264.665); /* gray-900 */
+
+  --color-muted: oklch(96.7% 0.003 264.542); /* gray-100 */
+  --color-muted-foreground: oklch(55.1% 0.027 264.364); /* gray-500 */
+
+  --color-accent: oklch(96.7% 0.003 264.542); /* gray-100 */
+  --color-accent-foreground: oklch(21% 0.034 264.665); /* gray-900 */
+
+  --color-destructive: oklch(57.7% 0.245 27.325); /* red-600 */
+  --color-destructive-foreground: oklch(98.5% 0.002 247.839); /* gray-50 */
+
+  /*
+    Kept at gray-200 to match the `border-color` compatibility rule in the base layer below, so
+    `border-border` renders identically to a border with no colour utility at all.
+  */
+  --color-border: oklch(92.8% 0.006 264.531); /* gray-200 */
+  --color-input: oklch(92.8% 0.006 264.531); /* gray-200 */
+  --color-ring: oklch(70.7% 0.022 261.325); /* gray-400 */
+
   --animate-accordion-up: accordion-up 0.2s ease-out;
   --animate-accordion-down: accordion-down 0.2s ease-out;
 
@@ -55,6 +104,47 @@
   }
 }
 
+/*
+  Dark-mode overrides for the tokens defined in `@theme` above.
+
+  Note this is currently inert: nothing in the app ever puts `.dark` on an ancestor. `next-themes` is
+  installed but no `ThemeProvider` is mounted (`root-layout.tsx` mounts MUI's), so `useTheme()` sits
+  at its `system` default and never writes a class. These values are still correct to define — the
+  ~425 `dark:` utilities already in the codebase are waiting on the same switch — but activating dark
+  mode is a separate change.
+*/
+@layer base {
+  .dark {
+    --color-background: oklch(13% 0.028 261.692); /* gray-950 */
+    --color-foreground: oklch(98.5% 0.002 247.839); /* gray-50 */
+
+    --color-card: oklch(21% 0.034 264.665); /* gray-900 */
+    --color-card-foreground: oklch(98.5% 0.002 247.839); /* gray-50 */
+
+    --color-popover: oklch(21% 0.034 264.665); /* gray-900 */
+    --color-popover-foreground: oklch(98.5% 0.002 247.839); /* gray-50 */
+
+    --color-primary: oklch(98.5% 0.002 247.839); /* gray-50 */
+    --color-primary-foreground: oklch(21% 0.034 264.665); /* gray-900 */
+
+    --color-secondary: oklch(27.8% 0.033 256.848); /* gray-800 */
+    --color-secondary-foreground: oklch(98.5% 0.002 247.839); /* gray-50 */
+
+    --color-muted: oklch(27.8% 0.033 256.848); /* gray-800 */
+    --color-muted-foreground: oklch(70.7% 0.022 261.325); /* gray-400 */
+
+    --color-accent: oklch(27.8% 0.033 256.848); /* gray-800 */
+    --color-accent-foreground: oklch(98.5% 0.002 247.839); /* gray-50 */
+
+    --color-destructive: oklch(70.4% 0.191 22.216); /* red-400 */
+    --color-destructive-foreground: oklch(98.5% 0.002 247.839); /* gray-50 */
+
+    --color-border: oklch(27.8% 0.033 256.848); /* gray-800 */
+    --color-input: oklch(27.8% 0.033 256.848); /* gray-800 */
+    --color-ring: oklch(44.6% 0.03 256.802); /* gray-600 */
+  }
+}
+
 /* shadcn charts styles */
 @layer base {
   :root {