When the website first loads, there’s about 12 white columns that each go from bottom to top of the screen to reveal the page and the content and when you click say ‘INFO’, the animation of the background kind of dropping in the same transition to reveal the page
Oh, now I see it. When I clicked the first time I didn’t watched the load animation.
That’s kinda easy to do on load. You’ll just need to animate some div blocks with position: absolute or position: fixed in the background and play around the z-index to make the foreground elements apear on top of the rectangles.
To make this work on page change you’ll have to get some custom code to delay the new page until the animation is done. I’m sure I saw this custom code delay in some @PixelGeek Youtube video.