diff --git a/tests/scripts/comments-rules.sh b/tests/scripts/comments-rules.sh
index 944a88c..4fb8f81 100755
--- a/tests/scripts/comments-rules.sh
+++ b/tests/scripts/comments-rules.sh
@@ -20,6 +20,16 @@ printf 'const a = 1 /* A comment\n   spanning lines. */\n' >"$work/apps/a/web/sr
 printf '// One two three four five six seven eight nine ten eleven.\n' >"$work/apps/a/web/src/a.js"
 ! check || fail "an eleven-word JS comment passed"
 rm "$work/apps/a/web/src/a.js"
+mkdir -p "$work/site/src"
+for ext in ts css; do
+  printf '/* A comment\n   spanning lines. */\n' >"$work/site/src/a.$ext"
+  ! check || fail "a multi-line .$ext block comment passed"
+  printf '/* One two three four five six seven eight nine ten eleven. */\n' >"$work/site/src/a.$ext"
+  ! check || fail "an eleven-word .$ext comment passed"
+  printf '/* One short line. */\n' >"$work/site/src/a.$ext"
+  check || fail "a short .$ext comment failed"
+  rm "$work/site/src/a.$ext"
+done
 printf '// One two three four five six seven eight nine ten eleven.\n' >"$work/tests/scripts/a.swift"
 ! check || fail "an eleven-word Swift comment passed"
 echo "ok: comment rules"
diff --git a/tests/scripts/comments.py b/tests/scripts/comments.py
index a85a59e..613ddce 100755
--- a/tests/scripts/comments.py
+++ b/tests/scripts/comments.py
@@ -65,7 +65,7 @@ for pattern in PATTERNS:
             if line.startswith("#!"):
                 continue
             # A block comment left open spans lines.
-            if path.suffix in (".c", ".h", ".js") and re.search(r"/\*(?!.*\*/)", line):
+            if path.suffix in (".c", ".h", ".js", ".ts", ".css") and re.search(r"/\*(?!.*\*/)", line):
                 repeated.setdefault(path, number)
             match = comment.match(line)
             said = match and next(group for group in match.groups() if group is not None)