diff --git a/lib/index.js b/lib/index.js
index 79d2a3f..1f0ac45 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,15 +1,17 @@
-const postcss = require('postcss');
-
-module.exports = postcss.plugin('postcss-header', (options = {}) => {
+module.exports = (options = {}) => {
   options = Object.assign({
     header: '',
   }, options);
 
-  return (css) => {
-    const header = options.header || options.banner;
+  return {
+    postcssPlugin: 'postcss-header',
+    Once(root) {
+      const header = options.header || options.banner;
 
-    if (header) {
-      css.prepend(header);
-    }
+      if (header) {
+        root.prepend(header);
+      }
+    },
   };
-});
+};
+module.exports.postcss = true;