Yes, add the body class in theme.liquid and also add the CSS at the end of head tag which is also in the same theme.liquid file.
@sb11 I agree with you. It’s not the ideal case. Just a quick fix. So I tried a different approach.
Shopify 2.0 is allowing .liquid templates as well. So you can create an LP with this template and use {% layout none %}. But this will disable the dynamic sections feature on the specific page. I also explored the alternative layouts option which boiled down to the same conclusion.