Thumbnails are not centralized on Safari and FF

[AlvMF1]

Steps to reproduce the behavior:
Open http://jossmac.github.io/react-images (with thumbnails example) on Safari 10.0.1 (macOS 10.12.1) or FireFox 50.0.

Expected behavior:
Thumbnails centralized. It works on Chrome 54.0.28.

Actual behavior:
Thumbnails are not centralized.

[jossmac]

@AlvMF1 thanks for the heads up

[triple1c86]

erm the bug still there in landscape mode.. not centralised.

[Viktor6713]

Still an issue in Safari. This css helps:
#lightboxBackdrop > div:nth-of-type(2) { left: 50%; transform: translateX(-50%); }

I would add this into paginatedThumbnails styles.

[neptunian]

this could be why: https://www.w3.org/TR/css-flexbox-1/#abspos-items
at least in safari. thanks @Viktor6713, i'll use your solution.