diff --git a/async.d.ts b/async.d.ts
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+++ b/async.d.ts
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+import { async as _async } from './index.js'
+
+declare const async: typeof _async
+
+export = async
diff --git a/index.d.mts b/index.d.mts
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+++ b/index.d.mts
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+export {
+  CssInJs,
+  ObjectifyOptions,
+  sync,
+  async,
+  objectify,
+  parse,
+  default
+} from './index.js'
diff --git a/index.d.ts b/index.d.ts
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+++ b/index.d.ts
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+// From DefinitelyTyped by Adam Thompson-Sharpe (https://github.com/MysteryBlokHed) with some modifications.
+import { AcceptedPlugin, Root } from 'postcss'
+
+declare namespace postcssJs {
+  /** CSS-in-JS object */
+  type CssInJs = Record<string, any>
+
+  /**
+   * Create a PostCSS processor with a simple API
+   * @param plugins Synchronous plugins to use with PostCSS
+   * @returns A processor function that accepts (idk) and returns a CSS-in-JS object
+   */
+  function sync(
+    plugins?: readonly AcceptedPlugin[]
+  ): (input: CssInJs) => CssInJs
+  function sync(...plugins: AcceptedPlugin[]): (input: CssInJs) => CssInJs
+
+  /**
+   * Create a PostCSS processor with a simple API, allowing asynchronous plugins
+   * @param plugins Plugins to use with PostCSS
+   * @returns A processor function that accepts (idk) and returns a CSS-in-JS object
+   */
+  function async(
+    plugins?: readonly AcceptedPlugin[]
+  ): (input: CssInJs) => Promise<CssInJs>
+  function async(
+    ...plugins: AcceptedPlugin[]
+  ): (input: CssInJs) => Promise<CssInJs>
+
+  /**
+   * Parse a CSS-in-JS object into a PostCSS `Root`
+   * @param obj The CSS-in-JS to parse
+   * @returns A PostCSS `Root`
+   */
+  function parse(obj: CssInJs): Root
+
+  interface ObjectifyOptions {
+    stringifyImportant?: boolean | undefined
+  }
+
+  /**
+   * Convert a PostCSS `Root` into a CSS-in-JS object
+   * @param root The root to convert
+   * @returns CSS-in-JS object
+   */
+  function objectify(root: Root, options?: ObjectifyOptions): CssInJs
+
+  export {
+    CssInJs,
+    ObjectifyOptions,
+    sync,
+    async,
+    objectify,
+    parse,
+    postcssJs as default
+  }
+}
+
+export = postcssJs
diff --git a/objectifier.d.ts b/objectifier.d.ts
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+++ b/objectifier.d.ts
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+import { ObjectifyOptions, objectifiy } from './index.js'
+
+declare namespace objectifier {
+  export { ObjectifyOptions, objectifiy as default }
+}
+
+export = objectifier
diff --git a/parser.d.ts b/parser.d.ts
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--- /dev/null
+++ b/parser.d.ts
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+import { parse } from './index.js'
+
+declare const parser: typeof parse
+
+export = parser
diff --git a/process-result.d.ts b/process-result.d.ts
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--- /dev/null
+++ b/process-result.d.ts
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+import { CssInJs } from './index.js'
+import { LazyResult } from 'postcss'
+import NoWorkResult from 'postcss/lib/no-work-result'
+
+declare function processResult(result: LazyResult | NoWorkResult): CssInJs
+
+export = processResult
diff --git a/sync.d.ts b/sync.d.ts
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--- /dev/null
+++ b/sync.d.ts
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+import { sync as _sync } from './index.js'
+
+declare const sync: typeof _sync
+
+export = sync