diff --git a/README.md b/README.md
index 8f74083..3a74802 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,8 @@
 
 ## overview
 
-Forge is a typed, local, variant-driven way to organize CSS, built around TSX.
+Forge is a typed, local, variant-driven way to organize CSS and create
+self-contained TSX components out of discrete parts.
 
 ## css problems
 
@@ -24,7 +25,8 @@ Forge is a typed, local, variant-driven way to organize CSS, built around TSX.
 - Component styles are made up of independently styled "Parts".
 - "Variants" replace inline styles with typed, declarative parameters.
 - Style composition is deterministic.
-- Errors and feedback.
+- Themes are easy.
+- Errors and feedback are provided.
 
 ## examples
 
diff --git a/examples/button.tsx b/examples/button.tsx
index 5300a29..f2ca113 100644
--- a/examples/button.tsx
+++ b/examples/button.tsx
@@ -1,20 +1,21 @@
 import { createScope } from '../src'
-import { ExampleSection, theme } from './ssr/helpers'
+import { ExampleSection } from './ssr/helpers'
+import { theme } from './ssr/themes'
 
 const { define } = createScope('Button')
 
 const Button = define('Root', {
   base: 'button',
 
-  padding: `${theme.spacing.sm}px ${theme.spacing.lg}px`,
+  padding: `${theme('spacing-sm')} ${theme('spacing-lg')}`,
   display: "inline-flex",
   alignItems: "center",
   justifyContent: "center",
-  gap: theme.spacing.xs,
-  background: theme.colors.accent,
-  color: theme.colors.bg,
-  border: `1px solid ${theme.colors.accent}`,
-  borderRadius: theme.radius.sm,
+  gap: theme('spacing-xs'),
+  background: theme('colors-accent'),
+  color: theme('colors-bg'),
+  border: `1px solid ${theme('colors-accent')}`,
+  borderRadius: theme('radius-sm'),
   fontSize: 14,
   fontWeight: 400,
   cursor: "pointer",
@@ -23,8 +24,8 @@ const Button = define('Root', {
 
   states: {
     ":not(:disabled):hover": {
-      background: theme.colors.accentDim,
-      borderColor: theme.colors.accentDim,
+      background: theme('colors-accentDim'),
+      borderColor: theme('colors-accentDim'),
     },
     ":not(:disabled):active": {
       transform: 'translateY(1px)',
@@ -34,23 +35,23 @@ const Button = define('Root', {
   variants: {
     intent: {
       primary: {
-        background: theme.colors.accent,
-        color: theme.colors.bg,
-        border: `1px solid ${theme.colors.accent}`,
+        background: theme('colors-accent'),
+        color: theme('colors-bg'),
+        border: `1px solid ${theme('colors-accent')}`,
       },
       secondary: {
-        background: theme.colors.bgElevated,
-        color: theme.colors.fg,
-        border: `1px solid ${theme.colors.border}`,
+        background: theme('colors-bgElevated'),
+        color: theme('colors-fg'),
+        border: `1px solid ${theme('colors-border')}`,
         states: {
           ":not(:disabled):hover": {
-            borderColor: theme.colors.borderActive,
+            borderColor: theme('colors-borderActive'),
           }
         }
       },
       danger: {
         background: "#ff0000",
-        color: theme.colors.bg,
+        color: theme('colors-bg'),
         border: "1px solid #ff0000",
         states: {
           ":not(:disabled):hover": {
@@ -61,23 +62,23 @@ const Button = define('Root', {
       },
       ghost: {
         background: "transparent",
-        color: theme.colors.fgMuted,
-        border: `1px solid ${theme.colors.border}`,
+        color: theme('colors-fgMuted'),
+        border: `1px solid ${theme('colors-border')}`,
         states: {
           ":not(:disabled):hover": {
-            color: theme.colors.fg,
-            borderColor: theme.colors.borderActive,
+            color: theme('colors-fg'),
+            borderColor: theme('colors-borderActive'),
           }
         }
       },
     },
     size: {
       small: {
-        padding: `${theme.spacing.xs}px ${theme.spacing.md}px`,
+        padding: `${theme('spacing-xs')} ${theme('spacing-md')}`,
         fontSize: 12,
       },
       large: {
-        padding: `${theme.spacing.md}px ${theme.spacing.xl}px`,
+        padding: `${theme('spacing-md')} ${theme('spacing-xl')}`,
         fontSize: 16,
       },
     },
@@ -90,7 +91,7 @@ const Button = define('Root', {
 
 const ButtonRow = define('Row', {
   display: 'flex',
-  gap: theme.spacing.md,
+  gap: theme('spacing-md'),
   flexWrap: 'wrap',
   alignItems: 'center',
 })
diff --git a/examples/form.tsx b/examples/form.tsx
index 65f1873..7feb2c7 100644
--- a/examples/form.tsx
+++ b/examples/form.tsx
@@ -1,15 +1,16 @@
 import { define } from '../src'
-import { ExampleSection, theme } from './ssr/helpers'
+import { ExampleSection } from './ssr/helpers'
+import { theme } from './ssr/themes'
 
 const Input = define('Input', {
   base: 'input',
 
-  padding: `${theme.spacing.sm}px ${theme.spacing.md}px`,
+  padding: `${theme('spacing-sm')} ${theme('spacing-md')}`,
   fontSize: 14,
-  border: `1px solid ${theme.colors.border}`,
-  borderRadius: theme.radius.sm,
-  background: theme.colors.bgElevated,
-  color: theme.colors.fg,
+  border: `1px solid ${theme('colors-border')}`,
+  borderRadius: theme('radius-sm'),
+  background: theme('colors-bgElevated'),
+  color: theme('colors-fg'),
   transition: 'all 0.2s ease',
   width: '100%',
   boxSizing: 'border-box',
@@ -17,11 +18,11 @@ const Input = define('Input', {
   states: {
     ':focus': {
       outline: 'none',
-      borderColor: theme.colors.borderActive,
+      borderColor: theme('colors-borderActive'),
     },
     ':disabled': {
-      background: theme.colors.bg,
-      color: theme.colors.fgDim,
+      background: theme('colors-bg'),
+      color: theme('colors-fgDim'),
       cursor: 'not-allowed'
     }
   },
@@ -37,10 +38,10 @@ const Input = define('Input', {
         }
       },
       success: {
-        borderColor: theme.colors.accent,
+        borderColor: theme('colors-accent'),
         states: {
           ':focus': {
-            borderColor: theme.colors.accent,
+            borderColor: theme('colors-accent'),
           }
         }
       }
@@ -51,12 +52,12 @@ const Input = define('Input', {
 const Textarea = define('Textarea', {
   base: 'textarea',
 
-  padding: `${theme.spacing.sm}px ${theme.spacing.md}px`,
+  padding: `${theme('spacing-sm')} ${theme('spacing-md')}`,
   fontSize: 14,
-  border: `1px solid ${theme.colors.border}`,
-  borderRadius: theme.radius.sm,
-  background: theme.colors.bgElevated,
-  color: theme.colors.fg,
+  border: `1px solid ${theme('colors-border')}`,
+  borderRadius: theme('radius-sm'),
+  background: theme('colors-bgElevated'),
+  color: theme('colors-fg'),
   transition: 'all 0.2s ease',
   width: '100%',
   minHeight: 120,
@@ -67,13 +68,13 @@ const Textarea = define('Textarea', {
   states: {
     ':focus': {
       outline: 'none',
-      borderColor: theme.colors.borderActive,
+      borderColor: theme('colors-borderActive'),
     }
   }
 })
 
 const FormGroup = define('FormGroup', {
-  marginBottom: theme.spacing.lg,
+  marginBottom: theme('spacing-lg'),
 
   parts: {
     Label: {
@@ -81,12 +82,12 @@ const FormGroup = define('FormGroup', {
       display: 'block',
       fontSize: 14,
       fontWeight: 400,
-      color: theme.colors.fg,
-      marginBottom: theme.spacing.xs
+      color: theme('colors-fg'),
+      marginBottom: theme('spacing-xs')
     },
     Helper: {
       fontSize: 12,
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       marginTop: 6
     },
     Error: {
@@ -120,21 +121,21 @@ const Checkbox = define('Checkbox', {
       base: 'label',
       display: 'flex',
       alignItems: 'center',
-      gap: theme.spacing.sm,
+      gap: theme('spacing-sm'),
       cursor: 'pointer',
       fontSize: 14,
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
 
       states: {
         ':hover': {
-          color: theme.colors.fg
+          color: theme('colors-fg')
         }
       },
 
       selectors: {
         '@Input:disabled + &': {
           cursor: 'not-allowed',
-          color: theme.colors.fgDim
+          color: theme('colors-fgDim')
         }
       }
     }
@@ -160,20 +161,20 @@ const FormExamples = define('FormExamples', {
 const Button = define('FormButton', {
   base: 'button',
 
-  padding: `${theme.spacing.sm}px ${theme.spacing.lg}px`,
+  padding: `${theme('spacing-sm')} ${theme('spacing-lg')}`,
   fontSize: 14,
   fontWeight: 400,
-  border: `1px solid ${theme.colors.accent}`,
-  borderRadius: theme.radius.sm,
+  border: `1px solid ${theme('colors-accent')}`,
+  borderRadius: theme('radius-sm'),
   cursor: 'pointer',
   transition: 'all 0.2s ease',
-  background: theme.colors.accent,
-  color: theme.colors.bg,
+  background: theme('colors-accent'),
+  color: theme('colors-bg'),
 
   states: {
     ':hover': {
-      background: theme.colors.accentDim,
-      borderColor: theme.colors.accentDim,
+      background: theme('colors-accentDim'),
+      borderColor: theme('colors-accentDim'),
     },
     ':active': {
       transform: 'translateY(1px)'
@@ -183,12 +184,12 @@ const Button = define('FormButton', {
   variants: {
     variant: {
       secondary: {
-        background: theme.colors.bgElevated,
-        color: theme.colors.fg,
-        border: `1px solid ${theme.colors.border}`,
+        background: theme('colors-bgElevated'),
+        color: theme('colors-fg'),
+        border: `1px solid ${theme('colors-border')}`,
         states: {
           ':hover': {
-            borderColor: theme.colors.borderActive,
+            borderColor: theme('colors-borderActive'),
           }
         }
       }
@@ -198,8 +199,8 @@ const Button = define('FormButton', {
 
 const ButtonGroup = define('FormButtonGroup', {
   display: 'flex',
-  gap: theme.spacing.sm,
-  marginTop: theme.spacing.lg
+  gap: theme('spacing-sm'),
+  marginTop: theme('spacing-lg')
 })
 
 export const FormExamplesContent = () => (
diff --git a/examples/navigation.tsx b/examples/navigation.tsx
index 780bec3..16be375 100644
--- a/examples/navigation.tsx
+++ b/examples/navigation.tsx
@@ -1,5 +1,6 @@
 import { define } from '../src'
-import { ExampleSection, theme } from './ssr/helpers'
+import { ExampleSection } from './ssr/helpers'
+import { theme } from './ssr/themes'
 
 const TabSwitcher = define('TabSwitcher', {
   parts: {
@@ -10,41 +11,41 @@ const TabSwitcher = define('TabSwitcher', {
     TabBar: {
       display: 'flex',
       gap: 0,
-      borderBottom: `1px solid ${theme.colors.border}`,
-      marginBottom: theme.spacing.lg,
+      borderBottom: `1px solid ${theme('colors-border')}`,
+      marginBottom: theme('spacing-lg'),
     },
     TabLabel: {
       base: 'label',
 
-      padding: `${theme.spacing.sm}px ${theme.spacing.lg}px`,
+      padding: `${theme('spacing-sm')} ${theme('spacing-lg')}`,
       position: 'relative',
       marginBottom: -1,
       background: 'transparent',
       borderBottom: '1px solid transparent',
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       fontSize: 14,
       cursor: 'pointer',
       transition: 'all 0.2s ease',
 
       states: {
         ':hover': {
-          color: theme.colors.fg,
+          color: theme('colors-fg'),
         }
       },
 
       selectors: {
         '@Input:checked + &': {
-          color: theme.colors.accent,
-          borderBottom: `1px solid ${theme.colors.accent}`
+          color: theme('colors-accent'),
+          borderBottom: `1px solid ${theme('colors-accent')}`
         }
       }
     },
     Content: {
       display: 'none',
-      padding: theme.spacing.lg,
-      background: theme.colors.bgElevated,
-      border: `1px solid ${theme.colors.border}`,
-      borderRadius: theme.radius.sm,
+      padding: theme('spacing-lg'),
+      background: theme('colors-bgElevated'),
+      border: `1px solid ${theme('colors-border')}`,
+      borderRadius: theme('radius-sm'),
 
       selectors: {
         '@Input:checked ~ &': {
@@ -91,37 +92,37 @@ const Pills = define('Pills', {
     },
     PillBar: {
       display: 'flex',
-      gap: theme.spacing.xs,
+      gap: theme('spacing-xs'),
       flexWrap: 'wrap',
     },
     PillLabel: {
       base: 'label',
 
-      padding: `${theme.spacing.xs}px ${theme.spacing.md}px`,
-      background: theme.colors.bgElevated,
-      border: `1px solid ${theme.colors.border}`,
+      padding: `${theme('spacing-xs')} ${theme('spacing-md')}`,
+      background: theme('colors-bgElevated'),
+      border: `1px solid ${theme('colors-border')}`,
       borderRadius: 20,
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       fontSize: 14,
       cursor: 'pointer',
       transition: 'all 0.2s ease',
 
       states: {
         ':hover': {
-          borderColor: theme.colors.borderActive,
-          color: theme.colors.fg,
+          borderColor: theme('colors-borderActive'),
+          color: theme('colors-fg'),
         }
       },
 
       selectors: {
         '@Input:checked + &': {
-          background: theme.colors.accent,
-          borderColor: theme.colors.accent,
-          color: theme.colors.bg
+          background: theme('colors-accent'),
+          borderColor: theme('colors-accent'),
+          color: theme('colors-bg')
         },
         '@Input:checked + &:hover': {
-          background: theme.colors.accentDim,
-          borderColor: theme.colors.accentDim,
+          background: theme('colors-accentDim'),
+          borderColor: theme('colors-accentDim'),
         }
       }
     }
@@ -165,36 +166,36 @@ const VerticalNav = define('VerticalNav', {
     NavLabel: {
       base: 'label',
 
-      padding: `${theme.spacing.sm}px ${theme.spacing.md}px`,
+      padding: `${theme('spacing-sm')} ${theme('spacing-md')}`,
       display: 'flex',
       alignItems: 'center',
-      gap: theme.spacing.sm,
+      gap: theme('spacing-sm'),
 
       background: 'transparent',
       border: `1px solid transparent`,
-      borderRadius: theme.radius.sm,
-      color: theme.colors.fgMuted,
+      borderRadius: theme('radius-sm'),
+      color: theme('colors-fgMuted'),
       fontSize: 14,
       cursor: 'pointer',
       transition: 'all 0.2s ease',
 
       states: {
         ':hover': {
-          background: theme.colors.bgElevated,
-          borderColor: theme.colors.border,
-          color: theme.colors.fg,
+          background: theme('colors-bgElevated'),
+          borderColor: theme('colors-border'),
+          color: theme('colors-fg'),
         }
       },
 
       selectors: {
         '@Input:checked + &': {
-          background: theme.colors.bgElevated,
-          borderColor: theme.colors.accent,
-          color: theme.colors.accent,
+          background: theme('colors-bgElevated'),
+          borderColor: theme('colors-accent'),
+          color: theme('colors-accent'),
         },
         '@Input:checked + &:hover': {
-          borderColor: theme.colors.accentDim,
-          color: theme.colors.accentDim
+          borderColor: theme('colors-accentDim'),
+          color: theme('colors-accentDim')
         }
       }
     },
@@ -235,31 +236,31 @@ const VerticalNav = define('VerticalNav', {
 const Breadcrumbs = define('Breadcrumbs', {
   display: 'flex',
   alignItems: 'center',
-  gap: theme.spacing.xs,
+  gap: theme('spacing-xs'),
   flexWrap: 'wrap',
 
   parts: {
     Item: {
       base: 'a',
 
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       fontSize: 14,
       textDecoration: 'none',
       transition: 'color 0.2s ease',
 
       states: {
         ':hover': {
-          color: theme.colors.accent,
+          color: theme('colors-accent'),
         }
       }
     },
     Separator: {
-      color: theme.colors.fgDim,
+      color: theme('colors-fgDim'),
       fontSize: 14,
       userSelect: 'none',
     },
     Current: {
-      color: theme.colors.fg,
+      color: theme('colors-fg'),
       fontSize: 14,
     }
   },
@@ -289,25 +290,25 @@ const Breadcrumbs = define('Breadcrumbs', {
 const Tabs = define('Tabs', {
   display: 'flex',
   gap: 0,
-  borderBottom: `1px solid ${theme.colors.border}`,
+  borderBottom: `1px solid ${theme('colors-border')}`,
 
   parts: {
     Tab: {
       base: 'button',
-      padding: `${theme.spacing.sm}px ${theme.spacing.lg}px`,
+      padding: `${theme('spacing-sm')} ${theme('spacing-lg')}`,
       position: 'relative',
       marginBottom: -1,
       background: 'transparent',
       border: 'none',
       borderBottom: '1px solid transparent',
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       fontSize: 14,
       cursor: 'pointer',
       transition: 'all 0.2s ease',
 
       states: {
         ':hover': {
-          color: theme.colors.fg,
+          color: theme('colors-fg'),
         }
       }
     }
@@ -317,8 +318,8 @@ const Tabs = define('Tabs', {
     active: {
       parts: {
         Tab: {
-          color: theme.colors.accent,
-          borderBottom: `1px solid ${theme.colors.accent}`,
+          color: theme('colors-accent'),
+          borderBottom: `1px solid ${theme('colors-accent')}`,
         }
       }
     }
@@ -339,25 +340,25 @@ const Tabs = define('Tabs', {
 
 const SimplePills = define('SimplePills', {
   display: 'flex',
-  gap: theme.spacing.xs,
+  gap: theme('spacing-xs'),
   flexWrap: 'wrap',
 
   parts: {
     Pill: {
       base: 'button',
-      padding: `${theme.spacing.xs}px ${theme.spacing.md}px`,
-      background: theme.colors.bgElevated,
-      border: `1px solid ${theme.colors.border}`,
+      padding: `${theme('spacing-xs')} ${theme('spacing-md')}`,
+      background: theme('colors-bgElevated'),
+      border: `1px solid ${theme('colors-border')}`,
       borderRadius: 20,
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       fontSize: 14,
       cursor: 'pointer',
       transition: 'all 0.2s ease',
 
       states: {
         ':hover': {
-          borderColor: theme.colors.borderActive,
-          color: theme.colors.fg,
+          borderColor: theme('colors-borderActive'),
+          color: theme('colors-fg'),
         }
       }
     }
@@ -367,13 +368,13 @@ const SimplePills = define('SimplePills', {
     active: {
       parts: {
         Pill: {
-          background: theme.colors.accent,
-          borderColor: theme.colors.accent,
-          color: theme.colors.bg,
+          background: theme('colors-accent'),
+          borderColor: theme('colors-accent'),
+          color: theme('colors-bg'),
           states: {
             ':hover': {
-              background: theme.colors.accentDim,
-              borderColor: theme.colors.accentDim,
+              background: theme('colors-accentDim'),
+              borderColor: theme('colors-accentDim'),
             }
           }
         }
@@ -403,14 +404,14 @@ const SimpleVerticalNav = define('SimpleVerticalNav', {
   parts: {
     NavItem: {
       base: 'button',
-      padding: `${theme.spacing.sm}px ${theme.spacing.md}px`,
+      padding: `${theme('spacing-sm')} ${theme('spacing-md')}`,
       display: 'flex',
       alignItems: 'center',
-      gap: theme.spacing.sm,
+      gap: theme('spacing-sm'),
       background: 'transparent',
       border: `1px solid transparent`,
-      borderRadius: theme.radius.sm,
-      color: theme.colors.fgMuted,
+      borderRadius: theme('radius-sm'),
+      color: theme('colors-fgMuted'),
       fontSize: 14,
       textAlign: 'left',
       cursor: 'pointer',
@@ -418,9 +419,9 @@ const SimpleVerticalNav = define('SimpleVerticalNav', {
 
       states: {
         ':hover': {
-          background: theme.colors.bgElevated,
-          borderColor: theme.colors.border,
-          color: theme.colors.fg,
+          background: theme('colors-bgElevated'),
+          borderColor: theme('colors-border'),
+          color: theme('colors-fg'),
         }
       }
     },
@@ -438,13 +439,13 @@ const SimpleVerticalNav = define('SimpleVerticalNav', {
     active: {
       parts: {
         NavItem: {
-          background: theme.colors.bgElevated,
-          borderColor: theme.colors.accent,
-          color: theme.colors.accent,
+          background: theme('colors-bgElevated'),
+          borderColor: theme('colors-accent'),
+          color: theme('colors-accent'),
           states: {
             ':hover': {
-              borderColor: theme.colors.accentDim,
-              color: theme.colors.accentDim,
+              borderColor: theme('colors-accentDim'),
+              color: theme('colors-accentDim'),
             }
           }
         }
diff --git a/examples/profile.tsx b/examples/profile.tsx
index 0c8a3e0..68e728c 100644
--- a/examples/profile.tsx
+++ b/examples/profile.tsx
@@ -1,22 +1,23 @@
 import { define } from '../src'
-import { ExampleSection, theme } from './ssr/helpers'
+import { ExampleSection } from './ssr/helpers'
+import { theme } from './ssr/themes'
 
 const UserProfile = define('UserProfile', {
   base: 'div',
 
-  padding: theme.spacing.lg,
+  padding: theme('spacing-lg'),
   maxWidth: 600,
   margin: "0 auto",
-  background: theme.colors.bgElevated,
-  border: `1px solid ${theme.colors.border}`,
-  borderRadius: theme.radius.md,
+  background: theme('colors-bgElevated'),
+  border: `1px solid ${theme('colors-border')}`,
+  borderRadius: theme('radius-md'),
 
   parts: {
     Header: {
       display: "flex",
       alignItems: "center",
-      gap: theme.spacing.md,
-      marginBottom: theme.spacing.md,
+      gap: theme('spacing-md'),
+      marginBottom: theme('spacing-md'),
     },
     Avatar: {
       base: 'img',
@@ -24,7 +25,7 @@ const UserProfile = define('UserProfile', {
       height: 64,
       borderRadius: "50%",
       objectFit: "cover",
-      border: `2px solid ${theme.colors.border}`,
+      border: `2px solid ${theme('colors-border')}`,
     },
     Info: {
       flex: 1,
@@ -33,25 +34,25 @@ const UserProfile = define('UserProfile', {
       marginBottom: 4,
       fontSize: 18,
       fontWeight: 400,
-      color: theme.colors.fg,
+      color: theme('colors-fg'),
     },
     Handle: {
       fontSize: 14,
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
     },
     Bio: {
-      marginBottom: theme.spacing.md,
+      marginBottom: theme('spacing-md'),
       width: "100%",
       fontSize: 14,
       lineHeight: 1.6,
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       wordWrap: "break-word",
     },
     Stats: {
       display: "flex",
-      gap: theme.spacing.lg,
-      paddingTop: theme.spacing.md,
-      borderTop: `1px solid ${theme.colors.border}`,
+      gap: theme('spacing-lg'),
+      paddingTop: theme('spacing-md'),
+      borderTop: `1px solid ${theme('colors-border')}`,
     },
     Stat: {
       display: "flex",
@@ -61,11 +62,11 @@ const UserProfile = define('UserProfile', {
     StatValue: {
       fontSize: 18,
       fontWeight: 400,
-      color: theme.colors.fg,
+      color: theme('colors-fg'),
     },
     StatLabel: {
       fontSize: 12,
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       textTransform: "uppercase",
     },
   },
@@ -114,7 +115,7 @@ const UserProfile = define('UserProfile', {
     verified: {
       parts: {
         Avatar: {
-          border: `2px solid ${theme.colors.accent}`,
+          border: `2px solid ${theme('colors-accent')}`,
         },
       },
     },
diff --git a/examples/spa/app.tsx b/examples/spa/app.tsx
index bc19758..465c12a 100644
--- a/examples/spa/app.tsx
+++ b/examples/spa/app.tsx
@@ -1,18 +1,68 @@
 import { define } from '../../src'
-import { theme } from '../ssr/helpers'
+import { theme } from '../ssr/themes'
 import { ButtonExamplesContent } from '../button'
 import { ProfileExamplesContent } from '../profile'
 import { NavigationExamplesContent } from '../navigation'
 import { FormExamplesContent } from '../form'
 
+// ThemePicker component
+const ThemePicker = define('SpaThemePicker', {
+  marginLeft: 'auto',
+
+  parts: {
+    Select: {
+      base: 'select',
+
+      padding: `${theme('spacing-xs')} ${theme('spacing-md')}`,
+      background: theme('colors-bgElevated'),
+      border: `1px solid ${theme('colors-border')}`,
+      borderRadius: theme('radius-sm'),
+      color: theme('colors-fg'),
+      fontSize: 14,
+      cursor: 'pointer',
+      transition: 'all 0.2s ease',
+
+      states: {
+        ':hover': {
+          borderColor: theme('colors-borderActive'),
+        },
+        ':focus': {
+          outline: 'none',
+          borderColor: theme('colors-borderActive'),
+        }
+      }
+    }
+  },
+
+  render({ parts: { Root, Select } }) {
+    const handleChange = (e: Event) => {
+      const target = e.target as HTMLSelectElement
+      const themeName = target.value
+      document.body.setAttribute('data-theme', themeName)
+      localStorage.setItem('theme', themeName)
+    }
+
+    return (
+      <Root>
+        <Select id="theme-select" onchange={handleChange}>
+          <option value="dark">Dark</option>
+          <option value="light">Light</option>
+        </Select>
+      </Root>
+    )
+  }
+})
+
 export const Main = define('SpaMain', {
   base: 'div',
 
   minHeight: '100%',
-  padding: theme.spacing.xl,
-  fontFamily: theme.fonts.mono,
-  background: theme.colors.bg,
-  color: theme.colors.fg,
+  height: '100%',
+  padding: theme('spacing-xl'),
+  fontFamily: theme('fonts-mono'),
+  background: theme('colors-bg'),
+  color: theme('colors-fg'),
+  boxSizing: 'border-box',
 })
 
 export const Container = define('SpaContainer', {
@@ -26,19 +76,19 @@ export const Container = define('SpaContainer', {
 const Link = define('Link', {
   base: 'a',
 
-  color: theme.colors.fgMuted,
+  color: theme('colors-fgMuted'),
   textDecoration: 'none',
   fontSize: 14,
 
   states: {
     hover: {
-      color: theme.colors.fg,
+      color: theme('colors-fg'),
     }
   },
 
   selectors: {
     '&[aria-current]': {
-      color: theme.colors.fg,
+      color: theme('colors-fg'),
       textDecoration: 'underline',
     }
   },
@@ -62,51 +112,51 @@ const Nav = define('Nav', {
   base: 'nav',
 
   display: 'flex',
-  gap: theme.spacing.lg,
-  marginBottom: theme.spacing.xl,
-  padding: theme.spacing.lg,
-  background: theme.colors.bgElevated,
-  border: `1px solid ${theme.colors.border}`,
-  borderRadius: theme.radius.sm,
+  gap: theme('spacing-lg'),
+  marginBottom: theme('spacing-xl'),
+  padding: theme('spacing-lg'),
+  background: theme('colors-bgElevated'),
+  border: `1px solid ${theme('colors-border')}`,
+  borderRadius: theme('radius-sm'),
 })
 
 const P = define('P', {
-  color: theme.colors.fgMuted,
+  color: theme('colors-fgMuted'),
   fontSize: 16,
-  marginBottom: theme.spacing.xxl,
+  marginBottom: theme('spacing-xxl'),
 })
 
 const ExamplesGrid = define('ExamplesGrid', {
   display: 'grid',
-  gap: theme.spacing.lg,
+  gap: theme('spacing-lg'),
   gridTemplateColumns: 'repeat(auto-fill, minmax(300px, 1fr))'
 })
 
 const ExampleCard = define('ExampleCard', {
   base: 'a',
 
-  background: theme.colors.bgElevated,
-  padding: theme.spacing.lg,
-  border: `1px solid ${theme.colors.border}`,
-  borderRadius: theme.radius.sm,
+  background: theme('colors-bgElevated'),
+  padding: theme('spacing-lg'),
+  border: `1px solid ${theme('colors-border')}`,
+  borderRadius: theme('radius-sm'),
   textDecoration: 'none',
   display: 'block',
 
   states: {
     hover: {
-      borderColor: theme.colors.borderActive,
+      borderColor: theme('colors-borderActive'),
     }
   },
 
   parts: {
     H2: {
-      color: theme.colors.fg,
-      margin: `0 0 ${theme.spacing.sm}px 0`,
+      color: theme('colors-fg'),
+      margin: `0 0 ${theme('spacing-sm')} 0`,
       fontSize: 18,
       fontWeight: 400,
     },
     P: {
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       margin: 0,
       fontSize: 14,
     }
@@ -182,13 +232,13 @@ export function route(path: string) {
 const HomeLink = define('HomeLink', {
   base: 'a',
 
-  color: theme.colors.fgMuted,
+  color: theme('colors-fgMuted'),
   textDecoration: 'none',
   fontSize: 14,
 
   states: {
     hover: {
-      color: theme.colors.fg,
+      color: theme('colors-fg'),
     }
   }
 })
@@ -206,6 +256,7 @@ export function App() {
           <Link href="/spa/buttons" aria-current={path === '/spa/buttons' ? 'page' : undefined}>Buttons</Link>
           <Link href="/spa/navigation" aria-current={path === '/spa/navigation' ? 'page' : undefined}>Navigation</Link>
           <Link href="/spa/form" aria-current={path === '/spa/form' ? 'page' : undefined}>Forms</Link>
+          <ThemePicker />
         </Nav>
         <div id="content">
           {route(path)}
diff --git a/examples/spa/index.html b/examples/spa/index.html
index 3d4dcd9..76805ec 100644
--- a/examples/spa/index.html
+++ b/examples/spa/index.html
@@ -3,16 +3,30 @@
 <head>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <link rel="stylesheet" href="/main.css"/>
   <title>Forge SPA Examples</title>
   <style>
     html, body {
       margin: 0;
+      height: 100%;
+    }
+    #root {
+      height: 100%;
     }
   </style>
 </head>
-<body>
+<body data-theme="dark">
   <div id="root"></div>
   <script type="module" src="/spa.js"></script>
+  <script>
+    // Load saved theme and apply it
+    const savedTheme = localStorage.getItem('theme') || 'dark'
+    document.body.setAttribute('data-theme', savedTheme)
+
+    // Set initial select value after page loads
+    window.addEventListener('load', () => {
+      const select = document.getElementById('theme-select')
+      if (select) select.value = savedTheme
+    })
+  </script>
 </body>
 </html>
diff --git a/examples/ssr/darkTheme.tsx b/examples/ssr/darkTheme.tsx
index 8bfe4cf..d7f5005 100644
--- a/examples/ssr/darkTheme.tsx
+++ b/examples/ssr/darkTheme.tsx
@@ -1,37 +1,30 @@
 export default {
-  colors: {
-    bg: '#0a0a0a',
-    bgElevated: '#111',
-    bgHover: '#1a1a1a',
+  'colors-bg': '#0a0a0a',
+  'colors-bgElevated': '#111',
+  'colors-bgHover': '#1a1a1a',
 
-    fg: '#00ff00',
-    fgMuted: '#888',
-    fgDim: '#444',
+  'colors-fg': '#00ff00',
+  'colors-fgMuted': '#888',
+  'colors-fgDim': '#444',
 
-    border: '#222',
-    borderActive: '#00ff00',
+  'colors-border': '#222',
+  'colors-borderActive': '#00ff00',
 
-    accent: '#00ff00',
-    accentDim: '#008800',
-  },
+  'colors-accent': '#00ff00',
+  'colors-accentDim': '#008800',
 
-  fonts: {
-    mono: "'Monaco', 'Menlo', 'Consolas', monospace",
-    sans: "-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif",
-  },
+  'fonts-mono': "'Monaco', 'Menlo', 'Consolas', monospace",
+  'fonts-sans': "-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif",
 
-  spacing: {
-    xs: 8,
-    sm: 12,
-    md: 16,
-    lg: 24,
-    xl: 32,
-    xxl: 48,
-  },
+  'spacing-xs': '8px',
+  'spacing-sm': '12px',
+  'spacing-md': '16px',
+  'spacing-lg': '24px',
+  'spacing-xl': '32px',
+  'spacing-xxl': '48px',
+
+  'radius-sm': '4px',
+  'radius-md': '8px',
+  'radius-lg': '12px',
+} as const
 
-  radius: {
-    sm: 4,
-    md: 8,
-    lg: 12,
-  }
-}
\ No newline at end of file
diff --git a/examples/ssr/helpers.tsx b/examples/ssr/helpers.tsx
index 223dc16..d811452 100644
--- a/examples/ssr/helpers.tsx
+++ b/examples/ssr/helpers.tsx
@@ -1,16 +1,14 @@
-import { define, Styles } from '../../src'
-import darkTheme from './darkTheme'
-
-export const theme = darkTheme
+import { define } from '../../src'
+import { theme } from './themes'
 
 export const Body = define('Body', {
   base: 'body',
 
   margin: 0,
-  padding: theme.spacing.xl,
-  fontFamily: theme.fonts.mono,
-  background: theme.colors.bg,
-  color: theme.colors.fg,
+  padding: theme('spacing-xl'),
+  fontFamily: theme('fonts-mono'),
+  background: theme('colors-bg'),
+  color: theme('colors-fg'),
 })
 
 const Container = define('Container', {
@@ -21,21 +19,21 @@ const Container = define('Container', {
 export const Header = define('Header', {
   base: 'h1',
 
-  marginBottom: theme.spacing.xl,
-  color: theme.colors.fg,
+  marginBottom: theme('spacing-xl'),
+  color: theme('colors-fg'),
   fontSize: 28,
   fontWeight: 400,
 })
 
 export const ExampleSection = define('ExampleSection', {
-  marginBottom: theme.spacing.xl,
+  marginBottom: theme('spacing-xl'),
 
   parts: {
     Header: {
       base: 'h2',
 
-      marginBottom: theme.spacing.md,
-      color: theme.colors.fgMuted,
+      marginBottom: theme('spacing-md'),
+      color: theme('colors-fgMuted'),
       fontSize: 16,
       fontWeight: 400,
     }
@@ -54,39 +52,96 @@ const Nav = define({
   base: 'nav',
 
   display: 'flex',
-  gap: theme.spacing.lg,
-  marginBottom: theme.spacing.xl,
-  padding: theme.spacing.lg,
-  background: theme.colors.bgElevated,
-  border: `1px solid ${theme.colors.border}`,
-  borderRadius: theme.radius.sm,
+  gap: theme('spacing-lg'),
+  marginBottom: theme('spacing-xl'),
+  padding: theme('spacing-lg'),
+  background: theme('colors-bgElevated'),
+  border: `1px solid ${theme('colors-border')}`,
+  borderRadius: theme('radius-sm'),
 })
 
 const NavLink = define({
   base: 'a',
 
-  color: theme.colors.fgMuted,
+  color: theme('colors-fgMuted'),
   textDecoration: 'none',
   fontSize: 14,
 
   states: {
     hover: {
-      color: theme.colors.fg,
+      color: theme('colors-fg'),
     }
   },
 
   selectors: {
     '&[aria-current]': {
-      color: theme.colors.fg,
+      color: theme('colors-fg'),
       textDecoration: 'underline',
     }
   }
 })
 
+const ThemePicker = define('ThemePicker', {
+  marginLeft: 'auto',
+
+  parts: {
+    Select: {
+      base: 'select',
+
+      padding: `${theme('spacing-xs')} ${theme('spacing-md')}`,
+      background: theme('colors-bgElevated'),
+      border: `1px solid ${theme('colors-border')}`,
+      borderRadius: theme('radius-sm'),
+      color: theme('colors-fg'),
+      fontSize: 14,
+      cursor: 'pointer',
+      transition: 'all 0.2s ease',
+
+      states: {
+        ':hover': {
+          borderColor: theme('colors-borderActive'),
+        },
+        ':focus': {
+          outline: 'none',
+          borderColor: theme('colors-borderActive'),
+        }
+      }
+    }
+  },
+
+  render({ parts: { Root, Select } }) {
+    return (
+      <Root>
+        <Select id="theme-select" onchange="window.switchTheme(this.value)">
+          <option value="dark">Dark</option>
+          <option value="light">Light</option>
+        </Select>
+      </Root>
+    )
+  }
+})
+
 export const Layout = define({
   render({ props }) {
     const path = props.path || ''
 
+    const themeScript = `
+      function switchTheme(themeName) {
+        document.body.setAttribute('data-theme', themeName)
+        localStorage.setItem('theme', themeName)
+      }
+
+      window.switchTheme = switchTheme
+
+      // Load saved theme or default to dark
+      const savedTheme = localStorage.getItem('theme') || 'dark'
+      document.body.setAttribute('data-theme', savedTheme)
+
+      // Set initial select value
+      const select = document.getElementById('theme-select')
+      if (select) select.value = savedTheme
+    `
+
     return (
       <html>
         <head>
@@ -104,10 +159,12 @@ export const Layout = define({
               <NavLink href="/ssr/buttons" aria-current={path === '/ssr/buttons' ? 'page' : undefined}>Buttons</NavLink>
               <NavLink href="/ssr/navigation" aria-current={path === '/ssr/navigation' ? 'page' : undefined}>Navigation</NavLink>
               <NavLink href="/ssr/form" aria-current={path === '/ssr/form' ? 'page' : undefined}>Forms</NavLink>
+              <ThemePicker />
             </Nav>
             <Header>{props.title}</Header>
             {props.children}
           </Container>
+          <script dangerouslySetInnerHTML={{ __html: themeScript }}></script>
         </Body>
       </html>
     )
diff --git a/examples/ssr/landing.tsx b/examples/ssr/landing.tsx
index 817b63f..a1bc30a 100644
--- a/examples/ssr/landing.tsx
+++ b/examples/ssr/landing.tsx
@@ -1,5 +1,5 @@
 import { createScope, Styles } from '../../src'
-import { theme } from './helpers'
+import { theme } from './themes'
 
 const { define } = createScope('Landing')
 
@@ -7,11 +7,11 @@ const Page = define('Page', {
   base: 'body',
 
   margin: 0,
-  padding: theme.spacing.xl,
+  padding: theme('spacing-xl'),
   minHeight: '100vh',
-  fontFamily: theme.fonts.mono,
-  background: theme.colors.bg,
-  color: theme.colors.fg,
+  fontFamily: theme('fonts-mono'),
+  background: theme('colors-bg'),
+  color: theme('colors-fg'),
 })
 
 const Container = define('Container', {
@@ -24,8 +24,8 @@ const Pre = define('Pre', {
 
   fontSize: 14,
   lineHeight: 1.4,
-  marginBottom: theme.spacing.xl,
-  color: theme.colors.fg,
+  marginBottom: theme('spacing-xl'),
+  color: theme('colors-fg'),
   whiteSpace: 'pre',
 })
 
@@ -34,66 +34,82 @@ const P = define('P', {
 
   fontSize: 16,
   lineHeight: 1.6,
-  marginBottom: theme.spacing.xl,
-  color: theme.colors.fgMuted,
+  marginBottom: theme('spacing-xl'),
+  color: theme('colors-fgMuted'),
 })
 
 const LinkSection = define('LinkSection', {
-  marginTop: theme.spacing.xxl,
-  paddingTop: theme.spacing.xl,
-  borderTop: `1px solid ${theme.colors.border}`,
+  marginTop: theme('spacing-xxl'),
+  paddingTop: theme('spacing-xl'),
+  borderTop: `1px solid ${theme('colors-border')}`,
 })
 
 const Link = define('Link', {
   base: 'a',
 
   display: 'inline-block',
-  marginRight: theme.spacing.xl,
-  padding: `${theme.spacing.sm}px ${theme.spacing.lg}px`,
-  background: theme.colors.bgElevated,
-  border: `1px solid ${theme.colors.border}`,
-  color: theme.colors.fg,
+  marginRight: theme('spacing-xl'),
+  padding: `${theme('spacing-sm')} ${theme('spacing-lg')}`,
+  background: theme('colors-bgElevated'),
+  border: `1px solid ${theme('colors-border')}`,
+  color: theme('colors-fg'),
   textDecoration: 'none',
   fontSize: 14,
 
   states: {
     ':hover': {
-      background: theme.colors.bgHover,
-      borderColor: theme.colors.borderActive,
+      background: theme('colors-bgHover'),
+      borderColor: theme('colors-borderActive'),
     }
   }
 })
 
-export const LandingPage = () => (
-  <html>
-    <head>
-      <meta charset="UTF-8" />
-      <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-      <title>forge</title>
-      <Styles />
-    </head>
-    <Page>
-      <Container>
-        <Pre>{`╔═╝╔═║╔═║╔═╝╔═╝
+export const LandingPage = () => {
+  const themeScript = `
+    function switchTheme(themeName) {
+      document.body.setAttribute('data-theme', themeName)
+      localStorage.setItem('theme', themeName)
+    }
+
+    window.switchTheme = switchTheme
+
+    // Load saved theme or default to dark
+    const savedTheme = localStorage.getItem('theme') || 'dark'
+    document.body.setAttribute('data-theme', savedTheme)
+  `
+
+  return (
+    <html>
+      <head>
+        <meta charset="UTF-8" />
+        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+        <title>forge</title>
+        <Styles />
+      </head>
+      <Page data-theme="dark">
+        <Container>
+          <Pre>{`╔═╝╔═║╔═║╔═╝╔═╝
 ╔═╝║ ║╔╔╝║ ║╔═╝
 ╝  ══╝╝ ╝══╝══╝`}</Pre>
 
-        <P>
-          Typed, local, variant-driven CSS. No globals, no selector hell, no inline styles.
-          Built for TSX. Compiles to real CSS.
-        </P>
+          <P>
+            Typed, local, variant-driven CSS. No globals, no selector hell, no inline styles.
+            Built for TSX. Compiles to real CSS.
+          </P>
 
-        <P>
-          CSS is hostile to humans at scale. Forge fixes that by making styles local,
-          typed, and composable. Parts replace selectors. Variants replace inline styles.
-          Everything deterministic.
-        </P>
+          <P>
+            CSS is hostile to humans at scale. Forge fixes that by making styles local,
+            typed, and composable. Parts replace selectors. Variants replace inline styles.
+            Everything deterministic.
+          </P>
 
-        <LinkSection>
-          <Link href="/ssr">SSR demos →</Link>
-          <Link href="/spa">SPA demos →</Link>
-        </LinkSection>
-      </Container>
-    </Page>
-  </html>
-)
+          <LinkSection>
+            <Link href="/ssr">SSR demos →</Link>
+            <Link href="/spa">SPA demos →</Link>
+          </LinkSection>
+        </Container>
+        <script dangerouslySetInnerHTML={{ __html: themeScript }}></script>
+      </Page>
+    </html>
+  )
+}
diff --git a/examples/ssr/lightTheme.tsx b/examples/ssr/lightTheme.tsx
new file mode 100644
index 0000000..cf46679
--- /dev/null
+++ b/examples/ssr/lightTheme.tsx
@@ -0,0 +1,29 @@
+export default {
+  'colors-bg': '#f5f5f0',
+  'colors-bgElevated': '#fff',
+  'colors-bgHover': '#e8e8e0',
+
+  'colors-fg': '#0a0a0a',
+  'colors-fgMuted': '#666',
+  'colors-fgDim': '#999',
+
+  'colors-border': '#ddd',
+  'colors-borderActive': '#008800',
+
+  'colors-accent': '#008800',
+  'colors-accentDim': '#00aa00',
+
+  'fonts-mono': "'Monaco', 'Menlo', 'Consolas', monospace",
+  'fonts-sans': "-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif",
+
+  'spacing-xs': '8px',
+  'spacing-sm': '12px',
+  'spacing-md': '16px',
+  'spacing-lg': '24px',
+  'spacing-xl': '32px',
+  'spacing-xxl': '48px',
+
+  'radius-sm': '4px',
+  'radius-md': '8px',
+  'radius-lg': '12px',
+} as const
\ No newline at end of file
diff --git a/examples/ssr/pages.tsx b/examples/ssr/pages.tsx
index cba68dd..ecfa0c8 100644
--- a/examples/ssr/pages.tsx
+++ b/examples/ssr/pages.tsx
@@ -1,47 +1,48 @@
 import { define } from '../../src'
-import { Layout, theme } from './helpers'
+import { Layout } from './helpers'
+import { theme } from './themes'
 import { ButtonExamplesContent } from '../button'
 import { ProfileExamplesContent } from '../profile'
 import { NavigationExamplesContent } from '../navigation'
 import { FormExamplesContent } from '../form'
 
 const P = define('SSR_P', {
-  color: theme.colors.fgMuted,
+  color: theme('colors-fgMuted'),
   fontSize: 16,
-  marginBottom: theme.spacing.xxl,
+  marginBottom: theme('spacing-xxl'),
 })
 
 const ExamplesGrid = define('SSR_ExamplesGrid', {
   display: 'grid',
-  gap: theme.spacing.lg,
+  gap: theme('spacing-lg'),
   gridTemplateColumns: 'repeat(auto-fill, minmax(300px, 1fr))'
 })
 
 const ExampleCard = define('SSR_ExampleCard', {
   base: 'a',
 
-  background: theme.colors.bgElevated,
-  padding: theme.spacing.lg,
-  border: `1px solid ${theme.colors.border}`,
-  borderRadius: theme.radius.sm,
+  background: theme('colors-bgElevated'),
+  padding: theme('spacing-lg'),
+  border: `1px solid ${theme('colors-border')}`,
+  borderRadius: theme('radius-sm'),
   textDecoration: 'none',
   display: 'block',
 
   states: {
     hover: {
-      borderColor: theme.colors.borderActive,
+      borderColor: theme('colors-borderActive'),
     }
   },
 
   parts: {
     H2: {
-      color: theme.colors.fg,
-      margin: `0 0 ${theme.spacing.sm}px 0`,
+      color: theme('colors-fg'),
+      margin: `0 0 ${theme('spacing-sm')} 0`,
       fontSize: 18,
       fontWeight: 400,
     },
     P: {
-      color: theme.colors.fgMuted,
+      color: theme('colors-fgMuted'),
       margin: 0,
       fontSize: 14,
     }
diff --git a/examples/ssr/themes.tsx b/examples/ssr/themes.tsx
new file mode 100644
index 0000000..d6aba63
--- /dev/null
+++ b/examples/ssr/themes.tsx
@@ -0,0 +1,10 @@
+import { createTheme, createThemedVar } from '../../src'
+import darkTheme from './darkTheme'
+import lightTheme from './lightTheme'
+
+// Register themes and get typed keys back
+const dark = createTheme('dark', darkTheme)
+const light = createTheme('light', lightTheme)
+
+// Create a typed themeVar function
+export const theme = createThemedVar({ dark, light })
\ No newline at end of file
diff --git a/src/index.tsx b/src/index.tsx
index a3149c6..1b3cbce 100644
--- a/src/index.tsx
+++ b/src/index.tsx
@@ -2,6 +2,58 @@ import type { JSX } from 'hono/jsx'
 import { type TagDef, UnitlessProps, NonStyleKeys } from './types'
 
 export const styles: Record<string, Record<string, string>> = {}
+const themes: Record<string, Record<string, any>> = {}
+
+// Type registry for theme variables (will be auto-populated)
+let registeredThemeKeys: Set<string> = new Set()
+
+// Clear all registered styles
+export function clearStyles() {
+  for (const key in styles) delete styles[key]
+}
+
+// Register a theme with CSS custom properties
+export function createTheme<const T extends Record<string, string | number>>(
+  name: string,
+  values: T
+): T {
+  themes[name] = values as Record<string, string>
+
+  // track for runtime validation
+  Object.keys(values).forEach(key => registeredThemeKeys.add(key))
+
+  return values
+}
+
+// Generate CSS for all registered themes
+export function themesToCSS(): string {
+  let out: string[] = []
+
+  for (const [name, vars] of Object.entries(themes)) {
+    out.push(`[data-theme="${name}"] {`)
+    for (const [key, value] of Object.entries(vars)) {
+      out.push(`  --theme-${key}: ${value};`)
+    }
+    out.push(`}\n`)
+  }
+
+  return out.join('\n')
+}
+
+// Helper type to extract theme keys from multiple theme objects
+type ThemeKeys<T> = T extends Record<string, any> ? keyof T : never
+
+// Create a typed themeVar function from your themes
+export function createThemedVar<T extends Record<string, any>>(_themes: T) {
+  return function themeVar<K extends ThemeKeys<T[keyof T]>>(name: K): string {
+    return `var(--theme-${name as string})`
+  }
+}
+
+// Generic themeVar (untyped fallback)
+export function themeVar(name: string): string {
+  return `var(--theme-${name as string})`
+}
 
 // All CSS styles inside <style></style.
 // Use w/ SSR: <Styles/>
@@ -29,6 +81,14 @@ function injectStylesInBrowser() {
 export function stylesToCSS(): string {
   let out: string[] = []
 
+  // Include theme CSS first
+  const themeCSS = themesToCSS()
+  if (themeCSS) {
+    out.push(themeCSS)
+    out.push('\n')
+  }
+
+  // Then component styles
   for (const [selector, style] of Object.entries(styles)) {
     if (Object.keys(style).length === 0) continue