Do not escape valid characters in custom CSS (#863)

bookmarks/views/custom_css.py

@@ -0,0 +1,10 @@
+from django.http import HttpResponse
+
+custom_css_cache_max_age = 2592000  # 30 days
+
+
+def custom_css(request):
+    css = request.user_profile.custom_css
+    response = HttpResponse(css, content_type="text/css")
+    response["Cache-Control"] = f"public, max-age={custom_css_cache_max_age}"
+    return response