how to insert container at bottom border in flutter code example

Example 1: add only bottom border to container flutter

decoration: BoxDecoration(
          border: Border(
            top: BorderSide(width: 16.0, color: Colors.lightBlue.shade600),
            bottom: BorderSide(width: 16.0, color: Colors.lightBlue.shade900),
          ),
          color: Colors.white,
        ),

Example 2: container border left

Container(
  decoration: BoxDecoration(
  	border: Border(
  		left: BorderSide(color: mainColor, width: 3),
  	),
  ),
),