@slidy/svelte - first render in firefox

[Valexr]

This seems to happen because: the list items do not receive the size of the images, and after the images are loaded, they are expanded to their size. @slidy/core also doesn't get the size of the target node's childs and spins what has arrived.

Just compare how it works in vanilla.
Even width: auto handles child sizes correctly as well.

Maybe the rules in CSS are missing some...🤷🏻‍♂️

[EricRovell]

b242277 fixes the bug. The problem was in .slidy-slides styles: justify-content was set for thumbs, it breaks the sizing of the slides. That was done some time ago to position the thumb at center when the edges of the carousel was moving too much apart.