Preview:
 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,
        ),
downloadDownload PNG downloadDownload JPEG downloadDownload SVG

Tip: You can change the style, width & colours of the snippet with the inspect tool before clicking Download!

Click to optimize width for Twitter