Starting recently new versions of Shopify theme will not have SASS based CSS files.

Even if you download a new version from the theme store if the liquid, or sass, version of theme.css still doesn't exist then most likely that theme has been converted to no longer use the .scss.liquid version as part of Shopify's depreciation of the SASS language in favour of a modern CSS standard workflow.

Anyway, we can work around it with theme.css or any better approach?