Based on this article, shopify decided to discontinue Sass, with the aim of improving the storefront user experience, and paving the way for future advancements. In the short term, Sass will continue to work on the Shopify theme, but we are actively migrating our theme to only use CSS style sheets.
We highlight the main point that removing Sass from the Shopify theme results in a significant speed increase when merchants interact with the Shopify theme editor. Depending on the size of the stylesheet, switching to a pure CSS approach can reduce page load times by a few seconds. The average compile time for Liquid Sass stylesheets in the editor is around 2,000 ms, while for Liquid CSS stylesheets it is only around 300 ms.
For more details you can read the article https://www.shopify.co.id/partners/blog/deprecating-sass.
Please check on the shopify theme that you are using, whether it is still using saas scss or is already css.
If your theme is still using saas then you need to update the theme. Or you do not understand how to that, please contact us.
Also, free support for clients we've worked with, this is your benefit!