The following is the code I searched from the Internet for the gradient of the background color of the web page from top to bottom to blue to white, but I don't understand some of the parameters. I can't figure out how to modify it if I want the gradient effect from bottom to top. Which parameter, I tried to modify the value of gradientType, but failed to achieve the gradient effect from bottom to top, only from left to right. I hope you can give me some advice, thank you in advance! !