diff --git a/datasette_auth_passwords/templates/password_login.html b/datasette_auth_passwords/templates/password_login.html
index f0c2bec..3467c75 100644
--- a/datasette_auth_passwords/templates/password_login.html
+++ b/datasette_auth_passwords/templates/password_login.html
@@ -28,7 +28,7 @@ <h1>Log in</h1>
     <p class="message-error">{{ error }}</p>
 {% endif %}
 
-<form class="password-login" action="{{ urls.path("/-/login") }}" method="post">
+<form class="password-login core" action="{{ urls.path("/-/login") }}" method="post">
     <div>
         <p>
             <label for="id_username">Username</label>
diff --git a/datasette_auth_passwords/templates/password_tool.html b/datasette_auth_passwords/templates/password_tool.html
index 0749831..bc0eb30 100644
--- a/datasette_auth_passwords/templates/password_tool.html
+++ b/datasette_auth_passwords/templates/password_tool.html
@@ -43,7 +43,7 @@ <h1>Password tool</h1>
     <textarea class="hashed-password">{{ hashed_password }}</textarea>
 {% endif %}
 
-<form action="/-/password-tool" method="post">
+<form class="core" action="/-/password-tool" method="post">
     <div>
         <input type="text" name="password" style="width: 40%" autocomplete="off">
         <input type="hidden" name="csrftoken" value="{{ csrftoken() }}">