What would be the most logical way of putting multiple radial gradients on one HTML element - html

Question

For a client I am trying to implement a background on an HTML element, which contains 2 radial gradients. One is located in the top right, one is located in the bottom left. My CSS only renders one of the radial gradients.
I have tried putting two radial gradient elements as a background:
body {
width: 100vw;
height: 100vh;
background-color: green;
background:
radial-gradient(
circle at top right,
red,
black 20%
),
radial-gradient(
circle at bottom left,
yellow,
orange 20%
);
}
Only the first radial-gradient appears, but the second one doesn't. When I switch the position of both gradients in de CSS markup, the colors change. So it appears as if only the first gradient is recognised.

Answer 1

I'm not sure which amount of color you want to see in the result, but my guess is you are after something like this.
body {
width: 100vw;
height: 100vh;
margin:0;
background-color: green;
background-image:
radial-gradient(
circle at top right,
red,
black 20%,
transparent 40%
),
radial-gradient(
circle at bottom left,
yellow,
orange 20%,
transparent 40%
);
}
One problem with your code was that you used the background shorthand for the background images, which resets the background color, so the green was no longer there. Use background-image instead.
Another was that both gradients covered the whole page, while you apparently want them to take up only the top right corner and bottom left corner instead. I solved this by giving them both transparent from 40%.
And I took the liberty of giving the body 0 margin, to get rid of the scrollbars.

Answer 2

My CSS only renders one of the radial gradients.
Simply because you are using opaque colors and by default a gradient will cover all the element so your will only see the top layer.
In addition to the answer of Mr Lister, you can adjust background-size to control the space each gradient should take:
body {
margin:0;
height: 100vh;
background:
radial-gradient(circle at top right, red, black 40%) right,
radial-gradient(circle at bottom left, yellow, orange 40%) left;
background-size:50% 100%;
background-repeat:no-repeat;
}
This looks a bit ugly but if you want to have a continuous background make sure both end color are the same:
body {
margin:0;
height: 100vh;
background:
radial-gradient(circle at top right , red, black 40%, green 60%) right,
radial-gradient(circle at bottom left, yellow, orange 40%, green 60%) left;
background-size:50.5% 100%;
background-repeat:no-repeat;
}