Gallery not showing when content is hidden at first

I made some simple html/css tabs using check box and tab content is showing only when its checkbox is checked while others are by default set to display:none;

Each tab contains a gallery but they are not showing when I click on other tabs, i.e. only active/checked tab is showing gallery.
See the video for demonstration in this link:

Btw, galleries that are not shown in tabs work just fine outside of tabs so I assume there is some problem when the content is set to display:none;.
Any idea how to sole this issue?

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