[#8546] Style statistics

[sevfurneaux]

Describe your changes This PR styles the statistics box

Tasks

• [x] PR name contains story or task reference
• [ ] Steps to recreate and test the changes
• [ ] Documentation (docs and inline)
• [ ] Tests (including n+1 and django_assert_num_queries where applicable)
• [x] Changelog

[sevfurneaux]

Nice job, I left just a few minor notes for you.

Thanks for the review, I've now made the changes 👍