How to use photoshop or illustrator or CSS to draw this?

In Powerpoint, it's easy to create this effect. [Gradient fill] -> [Rectangular]

If it is possible, can CSS do this? If not, I was wondering how I can do this in photoshop or illustrator with only a few steps?

The reason I need to do this is that I can't move the light beam to the middle top of the shape in powerpoint. It can only be on top right corner so I have to choose different softwares.

Thanks!