/* A gradient at the center of its container,
   starting red, changing to blue, and finishing green */
radial-gradient(circle at center, red 0, blue, green 100%)
Keyword     Description
closest-side     The gradient's ending shape meets the side of the box closest to its center (for circles) or meets both the vertical and horizontal sides closest to the center (for ellipses).
closest-corner     The gradient's ending shape is sized so that it exactly meets the closest corner of the box from its center.
farthest-side     Similar to closest-side, except the ending shape is sized to meet the side of the box farthest from its center (or vertical and horizontal sides).
farthest-corner     The default value, the gradient's ending shape is sized so that it exactly meets the farthest corner of the box from its center.