React body doesn't seem to get 100% height

Question

I wanted to find a solution to this peculiarity. I am trying to set a gradient background in the body of my application, but it seems that my body does not reach 100% of the screen and this causes a duplication of the background. I had never seen anything like this before, would anyone know why?

app.js:

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import * as serviceWorker from './serviceWorker';

ReactDOM.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>,
  document.getElementById('root')
);

serviceWorker.unregister();

App.js:

import React, { useState, useEffect } from 'react';
import { ClipLoader } from 'halogenium';
import {useSpring, animated} from 'react-spring'
import ComponentCentral from './components/componentCentral/ComponentCentral'
import './App.css';
import NavBar from './components/navbar/NavBar'
import Footer from './components/footer/Footer'

function App() {
    const estilo = useSpring({opacity: 1, from: {opacity: 0}})
    const [conteudoPage, setConteudoPage] = useState(<animated.div style={estilo}><ClipLoader className="loaderCircle" color="#26A65B" size="200px"/></animated.div>);
    const [usuario, setUsuario] = useState("");
    
    return (
        <div className="App">
            <NavBar usuario={usuario}></NavBar>
            {conteudoPage}
            <Footer></Footer>
        </div>
    );
}

export default App;

Index css:

html, body {
    padding: 0;
    margin : 0;
    width  : 100%;
    height: 100%;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    -webkit-font-smoothing : antialiased;
    -moz-osx-font-smoothing: grayscale;

    background       : linear-gradient(-45deg, #85FFBD 0%, #FFFB7D 100%);
    /* background-size: 200%; */
}

#root{
    height: 100%;
}

code {
    font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
        monospace;
}

hr {
    border          : 0;
    height          : 1px;
    background      : #333;
    background-image: linear-gradient(to right, #ccc, #333, #ccc);
    margin-top      : 25px
}

a.envelopeOK:link,
a.envelopeOK:visited {
    background-color: #84F0B9;
    color           : #135D36;
    padding         : 14px 25px;
    text-align      : center;
    text-decoration : none;
    display         : inline-block;
    border-radius   : 5px;
}

a.envelopeOK:hover,
a.envelopeOK:active {
    background-color: #41f397;
}

I'll send images of what happened

body image limit

image showing duplicate gradient

Would you know how to leave the body 100% for the gradient not to repeat?

EDIT:

Thanks to everyone who helped me, I unified some solutions and managed to solve my problem. As I'm working with react, I end up placing many nested divs where I only set body sizes and didn't let my other divs grow by themselves. My solution: put only default padding and margin 0 settings in the body and all the expansion part of the heigth and background I put in the body's daughter div: #root. With that, the body increases with the root div and it increases while the content is generated.

body {
padding: 0;
margin: 0;
}

#root {
min-height: 100vh;

font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
sans-serif;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;

background: linear-gradient (-45deg, # 85FFBD 0%, # FFFB7D 100%);
}

Answer 1

I checked your code Everything looks ok! What is this code for??

hr {
border          : 0;
height          : 1px;
background      : #333;
background-image: linear-gradient(to right, #ccc, #333, #ccc);
margin-top      : 25px
}

try removing this and see what happens.

Answer 2

Add a container in the body:

.container {
   height:100vh
}

Answer 3

由于我最终通过合并和测试工作人员的部分 css 来解决问题，因此我会将其留在编辑中，因为它已解决，谢谢大家！