velvet

On the click, a red curtain is drawn in from the right, its top leading and its hem trailing a little behind, while the page beside it dims, like a theatre’s lights. While the next page loads, its folds sway. Then it’s drawn back to the right, and the next page appears from the left, brightening. Going back looks the same.

A shader draws the curtain: its edge, the hem trailing most when it moves fastest, and folds that bunch up as the cloth gathers, lit from the upper left with a soft sheen. It keeps drawing while the page is covered, so the folds keep moving during the wait.