Welcome to the community. We’re delighted that you’re using Frontity.
To replicate the look of your WordPress theme in Frontity you will need to create a Frontity theme.
You have two approaches, find a theme which is similar and adapt and/or extend it, or create a theme from scratch.
When you install Frontity with
npx frontity create you are offered the choice of two themes - i.e.
twentytwenty-theme. Mars theme is a bare-bones minimal theme and is a great starting point for adapting and customising into the theme you want to create.
Alternatively you could search for
frontity theme on npmjs.com to find a theme which is close to what you want to end up with and start adapting that one.
The second approach would be to create a completely custom theme from scratch. Check out this tutorial which explains the process for doing that.
Finally, if you need to incorporate Bootstrap or other CSS into your Frontity theme check out this repo which demonstrates an example and should give you some guidance. In particular check out this file.
I hope the above helps.