diff --git a/core/templates/base.html b/core/templates/base.html
index 1fb66f6..72c2631 100644
--- a/core/templates/base.html
+++ b/core/templates/base.html
@@ -25,7 +25,12 @@
     <!-- Font Awesome 6 -->
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css">
     <!-- Custom CSS (cache-busted with deployment timestamp) -->
-    <link rel="stylesheet" href="{% static 'css/custom.css' %}?v={{ request.timestamp|default:'1.0' }}">
+    {# `deployment_timestamp` is provided by core.context_processors.project_context —
+       it's injected into every template so the browser (and any CDN in front of
+       the app) sees a fresh URL whenever the process restarts. The old template
+       used `request.timestamp` which doesn't exist on Django request objects and
+       always fell back to a fixed '1.0' — meaning CDNs cached the CSS forever. #}
+    <link rel="stylesheet" href="{% static 'css/custom.css' %}?v={{ deployment_timestamp|default:'1' }}">
 
     {% block extra_css %}{% endblock %}
 </head>