Linear Gradient - Top to Bottom (this is default)

#grad {
    background: red; /* For browsers that do not support gradients */
    background: -webkit-linear-gradient(red, yellow); /* For Safari 5.1 to 6.0 */
    background: -o-linear-gradient(red, yellow); /* For Opera 11.1 to 12.0 */
    background: -moz-linear-gradient(red, yellow); /* For Firefox 3.6 to 15 */
    background: linear-gradient(red, yellow); /* Standard syntax */
}



Linear Gradient - Left to Right

#grad {
  background: red; /* For browsers that do not support gradients */
  background: -webkit-linear-gradient(left, red , yellow); /* For Safari 5.1 to 6.0 */
  background: -o-linear-gradient(right, red, yellow); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(right, red, yellow); /* For Firefox 3.6 to 15 */
  background: linear-gradient(to right, red , yellow); /* Standard syntax */
}