Page created in Foogallery which generated a WP classic mode pg with the foogallery id inside a paragraph tag (removed later). Justified Gallery option. In single column view, eliminated additional padding on sides in settings / general, changed align to left instead of center.

Reduced text width to 80% width on desktop & tablet, 100% on mobile. Ordering–manually moved thumbnails.

Customize? when full size image displayed, thumbnails appear below but left-aligned where that block should be centered. Black background? Perplexity links to Foogallery’s customized CSS examples added to the gallery or globally. However, thus far they didn’t seem to work.