How can I make a ghostly gradient instead of this black background color?

Question

https://code.sololearn.com/WIrasBYX3XB5/?ref=app

Answer 1

You can modify the opacity value of the largest circle.

.circle {
opacity: 50%;
/*other stuff*/
}
You can also experiment with sepia or greyscale effects, search it up, it's interesting!

And yes, clearly the opacity works with the smiley face...

Answer 2

You mean the face of the smiley?