Enable gradient effect for context menu background.

shell {
    set {
        theme {
            background {
                opacity=80
                effect=1
                gradient
                {
                    enabled = true
                    linear = [0, 100, 0, 0]
                    stop = [
                        [0.0, color.accent_dark3, 90],
                        [0.5, color.accent, 90],
                        [1.0, color.accent_dark3, 90]
                    ]
                }
            }
        }
    }
}