diff --git a/examples/index.tsx b/examples/index.tsx
index eaf35dc..73f3f11 100644
--- a/examples/index.tsx
+++ b/examples/index.tsx
@@ -1,5 +1,4 @@
 import { define } from '../src'
-
 import { Layout } from './helpers'
 
 const P = define('P', {
@@ -46,10 +45,12 @@ const ExampleCard = define('ExampleCard', {
   },
 
   render({ props: { title, desc }, parts: { Root, H2, P } }) {
-    return <Root>
-      <H2>{title}</H2>
-      <P>{desc}</P>
-    </Root>
+    return (
+      <Root>
+        <H2>{title}</H2>
+        <P>{desc}</P>
+      </Root>
+    )
   }
 })
 
diff --git a/src/index.tsx b/src/index.tsx
index a4778c5..9b39377 100644
--- a/src/index.tsx
+++ b/src/index.tsx
@@ -161,6 +161,7 @@ export function define(nameOrDef: string | TagDef, defIfNamed?: TagDef) {
   const name = defIfNamed ? (nameOrDef as string) : `Def${anonComponents++}`
   const def = defIfNamed ?? nameOrDef as TagDef
 
+  if (styles[name]) throw `${name} is already defined! Must use unique names.`
   registerStyles(name, def)
 
   return (props: Record<string, any>) => {