diff --git a/std/http/file_server.ts b/std/http/file_server.ts
index 6a2d768056..10bb507cea 100755
--- a/std/http/file_server.ts
+++ b/std/http/file_server.ts
@@ -51,6 +51,7 @@ const MEDIA_TYPES: Record<string, string> = {
   ".js": "application/javascript",
   ".jsx": "text/jsx",
   ".gz": "application/gzip",
+  ".css": "text/css",
 };
 
 /** Returns the content-type based on the extension of a path. */