BackgroundColor of the Container only wrap the text inside Expanded Widget

I have a design like Pic 1,and my problem is that the text will be wrapped in a Container with background gradient, but since i'm using the Expanded to wrap this Container, so it's always get all the empty space like picture 2,which won't match the design.

If i'm using the Flexible,how can i align the arrow icon to the end of row as show in picture 3.
Please help me to find a solution, tks.

  Container(
              width: 400,
              height: 300,
              color: Colors.blue,
              child: Column(
                children: [
                  Padding(
                    padding: const EdgeInsets.all(16.0),
                    child: Row(
                      children: [
                        Flexible(
                            child: Container(
                                color: Colors.white,
                                child: Text("Công thực tế:21 công"))),
                        Align(
                            alignment: Alignment.topRight,
                            child: Icon(Icons.arrow_circle_right))
                      ],
                    ),
                  )
                ],
              ),
           ),

[Pic 1](https://i.stack.imgur.com/2HWAZ.png)
[Pic 2](https://i.stack.imgur.com/m5aQy.png)
[pic 3](https://i.stack.imgur.com/XUrrR.png)

Find a solution for this code

Ah, nevermind, i just found a solution, using the Flexible and MainAxisAlignment.spaceBetween, i will put my code below, thanks for your help.

Container(
            margin: EdgeInsets.fromLTRB(16, 16, 16, 0),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                Flexible(
                  child: Container(
                    color: Colors.white,
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Flexible(
                          child: Text("Công thực tế: 21 công"),
                        )
                      ],
                    ),
                  ),
                ),
                Container(
                  decoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(24),
                      border: Border.all(
                          width: 1, color: Colors.black.withOpacity(0.45))),
                  child: Icon(Icons.expand_more_outlined,
                      color: Colors.black.withOpacity(0.45)),
                ),
              ],
            ),
          )

you can try this:
output

child: Container(
       height: 200,
       width: 300,
       decoration: BoxDecoration(
         color: Colors.blue,
         borderRadius: BorderRadius.only(
           topRight: Radius.circular(10.0),
           bottomRight: Radius.circular(10.0),
           topLeft: Radius.circular(10.0),
           bottomLeft: Radius.circular(10.0),
         ),
       ),
       child: Padding(
         padding: const EdgeInsets.all(12.0),
         child: Column(
           children: [
             Row(
               mainAxisAlignment: MainAxisAlignment.spaceBetween,
               children: [
                 Container(
                   height: 50,
                   width: 200,
                   decoration: BoxDecoration(
                     color: Colors.blue.shade900,
                     borderRadius: BorderRadius.only(
                         topRight: Radius.circular(40.0),
                         bottomRight: Radius.circular(40.0),
                         topLeft: Radius.circular(40.0),
                         bottomLeft: Radius.circular(40.0),
                    ),
                   ),
                   child:
                   Center(child: Text('Text',style: TextStyle(color: Colors.white))),

  ),
                 CircleAvatar(
                   backgroundColor: Colors.blue.shade900,
                   radius: 20,
                   child: IconButton(
                     padding: EdgeInsets.zero,
                     icon: Icon(Icons.keyboard_arrow_up),
                     color: Colors.white,
                     onPressed: () {},
                   ),
                 ),
               ],
             ),
           ],
         ),
       ),
     ),