Cannot see anything on my Ionic App

I only see this on my browser when using ionic serve.

When I inspect element, I see that all the components are there:

I thought the following css is hiding my components:

html:not(.hydrated) body {
    display: none;
}

but, when I disable this css I see this:

I don’t see any errors in the console and so I don’t know what to do to fix this.

Thanks in advance!