diff --git a/cista/app.py b/cista/app.py
index 6df14c1..bb39b42 100755
--- a/cista/app.py
+++ b/cista/app.py
@@ -96,6 +96,10 @@ def _load_wwwroot(www):
             if name in www and www[name][2]["etag"] == etag:
                 wwwnew[name] = www[name]
                 continue
+            # Add charset definition
+            if mime.startswith("text/"):
+                mime = f"{mime}; charset=UTF-8"
+            # Asset files names will change whenever the content changes
             cached = name.startswith("assets/")
             headers = {
                 "etag": etag,