使用CSS，我会稍微修改qlineargradient.请注意，青色的边缘可能有点模糊.

With css I would hack qlineargradient a little bit. Note that edge of cyan may be a little blurry.

QFrame
{
        background-color: qlineargradient(x1:0, x2: 1, stop: 0 cyan, stop: 0.29 cyan, stop: 0.2901 white, stop: 1 white);
}