In Shopify, to include a custom CSS file without directly editing the base.css, you can link your custom CSS file by adding an @import rule to the base.css or the appropriate theme file. Here’s how:
Upload the Custom CSS File:
Go to your Shopify Admin > Online Store > Themes > Actions > Edit Code. In the Assets folder, click Add a new asset and upload your .css file.
Edit the base.css or theme.css File:
Locate the base.css or main CSS file in the Assets folder and add the following line at the top or where appropriate:
You can add this file to your theme by adding it below this file code to theme.liquid file. Below this line of code “{{ ‘base.css’ | asset_url | stylesheet_tag }}”