ReactJS 背景图像未显示

Question

The code inside the image below suppose give me the background. But it did not work. I don't get it why?

Image to the problem

Answer 1

.sign-in-container does not get 100% elevation. Because React have Root and you component inside root div on DOM. Root's height is not 100%. It is "auto".

You have to use "height: 100vh" instead of height: "100%" this project.

Answer 2

In your stylesheet you should reset the margin and padding of the html and body tags and set the height and width respectively to 100vh and 100vw like this

* {
    margin: 0;
    padding: 0;
}

html, body {
    width: 100vw;
    height: 100vh;
}

#root {
    width: 100%;
    height: 100%;
}