How do I obtain the top-grossing product for each individual vendor?

I came up with this so far and can't seem to proceed.

```
select vendor.Vendor_Name, Product.category AS Product
  , SUM(SalesFacts.Price * SalesFacts.Quantity) AS [Total Revenue]
FROM Vendor, Product, SalesFacts
WHERE SalesFacts.Vendor_Key = Vendor.Vendor_Key
AND SalesFacts.Product_Key = Product.Product_Key
GROUP BY vendor.Vendor_Name, product.Category
ORDER BY [Total Revenue] DESC;

```

![Vendor Table](https://i.stack.imgur.com/XIt7p.png)

![Product Table](https://i.stack.imgur.com/IP9HP.png)

![Sales Table](https://i.stack.imgur.com/VuNKh.png)

(Product\_Key and Vendor\_Key are Foreign Key)