Basic style of tooltip and popover when a specific item is hovered.
Tooltip is to provide an explanation for specific items, such as icon action, text, image explanation.
There are four values which define directions of a tooltip: top, right, bottom or left.
Popover is to provide short description about specific items, such as help, or details.
There are 4 values which define directions of a popover: top, right, bottom or left.
