Liquid Tube
A glass tube fills with liquid from the bottom, bubbles rise through it, and a sloshing wave crest rides the top while the percentage counts inside.
The liquid is a gradient div whose height is bound to the percentage, so it rises as loading progresses.
An SVG wave sits on top of the liquid and scrolls sideways on a loop for the sloshing crest.
Bubbles are small circles animated upward with staggered delays; the percentage text uses mix-blend so it stays readable over the liquid.