How do I create custom themes?

I’d like to add custom landing page and e-mail themes, so it’s part of the “coffee, mauve,nature” list when creating … I actually added these in a previous version of mautic, but after v1.3 my themes are working in a limited fashion now. I had customized in “builder.html” files in Pagebundle and EmailBundle Views folders, I used specific slots, and themes depended on the new slots… How do I implement the use of custom slots in the custom themes I create? Is there an updated documentation on how to further customize the themes? If you could point in the direction of where I should look to understand and customize the themes I’d appreciate it.

I’d like to add custom landing page and e-mail themes, so it’s part of the “coffee, mauve,nature” list when creating … I actually added these in a previous version of mautic, but after v1.3 my themes are working in a limited fashion now. I had customized in “builder.html” files in Pagebundle and EmailBundle Views folders, I used specific slots, and themes depended on the new slots… How do I implement the use of custom slots in the custom themes I create? Is there an updated documentation on how to further customize the themes? If you could point in the direction of where I should look to understand and customize the themes I’d appreciate it.