The CSS -moz-radial-gradient Mozilla extension property value was introduced in Gecko 1.9.2 (Firefox 3.6). Gradients are smooth transitions between two or more specified colors. Use of CSS gradients can replace images and reduce download time, create a more flexible layout, and look better while zooming. Firefox supports two kinds of CSS gradients: linear and radial. The -moz-radial-gradient property does not allow repeating gradients. For this functionality, see -moz-repeating-radial-gradient.