don't regenerate root every render

src/index.tsx

@@ -286,14 +286,18 @@ export function define(nameOrDef: string | TagDef, defIfNamed?: TagDef) {
   if (styles[`.${name}`]) throw `${name} is already defined! Must use unique names.`
   registerStyles(name, def)
 
+  const currentProps: Record<string, any> = {}
+  const Root = makeComponent(name, def, currentProps)
+
   return (props: Record<string, any>) => {
-    const parts: Record<string, Function> = {}
+    for (const key in currentProps) delete currentProps[key]
+    Object.assign(currentProps, props)
+    const parts: Record<string, Function> = { Root }
 
     for (const [part] of Object.entries(def.parts ?? {}))
       parts[part] = makeComponent(name, def, props, part)
 
-    parts.Root = makeComponent(name, def, props)
-    return def.render?.({ props, parts }) ?? <parts.Root {...props}>{props.children}</parts.Root>
+    return def.render?.({ props, parts }) ?? <Root {...props}>{props.children}</Root>
   }
 }