Function linear_gradient 

pub fn linear_gradient(
    angle: f32,
    from: impl Into<LinearColorStop>,
    to: impl Into<LinearColorStop>,
) -> Background

Creates a LinearGradient background color.

The gradient line’s angle of direction. A value of 0. is equivalent to top; increasing values rotate clockwise from there.

The angle is in degrees value in the range 0.0 to 360.0.

https://developer.mozilla.org/en-US/docs/Web/CSS/gradient/linear-gradient