Specifies the alignment of item content within the Timeline.
After - Aligns item content to the bottom and opposite content to the top when the Timeline is in a horizontal orientation, or the content to the right and opposite content to the left when the Timeline is in a vertical orientation.Alternate - Aligns item content alternatively, regardless of the Timeline’s orientation.AlternateReverse - Aligns item content in alternate reverse, regardless of the Timeline’s orientation.Before - Aligns item content to the top and opposite content to the bottom when the Timeline is in a horizontal orientation, or the content to the left and opposite content to the right when the Timeline is in a vertical orientation.