You will have to do the same thing with the reference(href) of the link tag that fetches Snipcart's stylesheet.
The snippets of code on your site will now look like:
<script src="https://cdn.snipcart.com/scripts/2.0/snipcart.js" data-api-key="YOUR_API_KEY" id="snipcart"></script> <link href="https://cdn.snipcart.com/themes/2.0/base/snipcart.min.css" rel="stylesheet" type="text/css" />
Instead of this:
Upgrading your cart version will enable more functionalities for your store. However, previous style customization from the v1.0 won't be supported once you've made the switch.
Improving our customization workflow came with a cost; the changes we introduced were too disruptive to support v1.0 customization in the v2.0.
But know that it is now way faster to come up with deep cart customizations! You can read more about this here.