HMR for CSS changes doesn't seem to be working

[cmalven]

Steps to reproduce:

• Create a new CSA project with either the @snowpack/app-template-11ty or @snowpack/app-template-blank templates – I assume the same may be true of the other templates but I've only tested these two.
• Start the dev environment
• Make a change to the index.css file, such as changing the background-color

Expected behavior:

• Change is applied without a full browser refresh

Actual behavior:

• Browser is refreshed, evidenced by the brief change in the refresh button in the browse, that the javascript-based confetti triggers again, and that the javascript console is cleared.