diff --git a/app/src/Database.php b/app/src/Database.php
index 9656e29..ebdc1fa 100644
--- a/app/src/Database.php
+++ b/app/src/Database.php
@@ -694,8 +694,9 @@ class Database
         $allFi = array_column($exec('SELECT name FROM finality_types ORDER BY name', []), 'name');
         $fiOut = array_map(fn ($n) => ['value' => $n, 'matched' => in_array($n, $matchedFiIds, true)], $allFi);
 
-        // Keywords
-        [$w, $b] = $buildWhere('kw');
+        // Keywords — many-to-many: use full intersection so that selecting
+        // a keyword filters the available set to only co-occurring keywords.
+        [$w, $b] = $buildWhere('__none__');
         $matchedKw = array_column($exec(
             "SELECT DISTINCT tg.name $baseJoins
              JOIN thesis_tags tt ON tt.thesis_id = t.id