When I run the build command with my problematic code, during build time I get this error:
TypeError: Cannot read properties of null (reading 'default')
After a bit of digging, I found out that the <slot> element in layouts\main.astro is causing the issue, however, I don't know why - the basics template has an <slot> element and that works just fine...
A repository of the problematic code: https://github.com/alipex/SlotIssueAstro
Any ideas for a fix? Thank you!