Como deixar o Gradiente transparente ?

Jorge,

As I (mis)understand it, The colour transition (beige to black) and the opacity/transparency transition (full opacity to full transparency) work in opposite directions.

This gives the strange transition starting with a greying of the beige (transition towards black), continuing in a darkening (owing to black being darker/denser than beige) along with a fuller greying, ending in a fading into nothing of the fully grey/diluted black.

So, the colour actually ends as a full black, only there is nothing left of it because it is also fully transparent.

"it is white as transparency"

Mayby what puzzles you is: at the end you are actually looking at the background which appears white(ish) because the gradient has finally withdrawn fully.

You can also say that the end transparency is a full black that is not there.

This nonsense may make more sense if you hide the image and look at the gradient in front of a white background.

I hope this sounds sufficiently woolly and unintelligible.