diff --git a/web/core/views.py b/web/core/views.py
index dfc7012..061d16b 100644
--- a/web/core/views.py
+++ b/web/core/views.py
@@ -1049,4 +1049,29 @@ is_superuser = user_passes_test(lambda u: u.is_superuser)
 @login_required
 def audit_log(request):
     rows = AuditLog.objects.all().order_by("-timestamp")[:100]
-    return render(request, "tools/audit_log.html", {"rows": rows})
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+    return render(request, "tools/audit_log.html", {"rows": rows})
+
+
+from django.contrib.staticfiles import finders
+from django.http import HttpResponseBadRequest, HttpResponseRedirect
+from django.urls import reverse
+import os
+
+def _is_valid_theme(name: str) -> bool:
+    # Validate against files present in /static/themes
+    for finder in finders.get_finders():
+        for path, storage in finder.list(['themes']):
+            if path == f'themes/{name}.css':
+                return True
+    return False
+
+def set_theme(request):
+    if request.method != 'POST':
+        return HttpResponseBadRequest('Invalid method')
+    theme = (request.POST.get('theme') or '').strip()
+    if not _is_valid_theme(theme):
+        return HttpResponseBadRequest('Unknown theme')
+    request.session['theme'] = theme
+    # also write to localStorage on next load via inline script in base.html
+    # redirect back to settings
+    return HttpResponseRedirect(reverse('settings'))  # adjust to your settings view name/URL
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