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                <div id="app"></div>


                body {
  margin: 0;
  font-family: 'Open Sans', sans-serif;

.app {
  position: relative;
  height: 100vh;
  background-color: #041d3e;
  transition: all 0.3s linear;

.app__years {
  width: 80%;
  margin-left: 10%;
  text-align: center;
  z-index: 2;
  position: relative;

.app__years__item {
  display: inline-block;
  margin: 8px;
  padding: 5px 8px;
  color: white;
  border-radius: 15px;
  border: 2px solid transparent;
  transition: all 0.3s linear;
  cursor: pointer;



                const {Component} = React;

const DATA = {
  "1880": { pirates: 20000, temperature: 14.5 },
  "1920": { pirates: 15000, temperature: 15.0 },
  "1940": { pirates: 5000, temperature: 15.3 },
  "1980": { pirates: 400, temperature: 15.7 },
  "2000": { pirates: 17, temperature: 16 },

class App extends Component {
  constructor(props) {
    // Questo è il modo in cui si definiscono i dati dello State
    this.state = {
      selectedYear: null
  renderYearbuttons(year) {
    // Questo metodo contiene html pur non essendo il metodo 'render'.
    // E' possibile, poiché la return di questo metodo avverrà all'interno
    // della 'render', di conseguenza questo codice html si troverà nel posto giusto.
    // Quell'attributo 'key' serve a React per definire in modo univoco ogni div generato dalla funzione 'map'
    return (
        { year }

  render() {
    return (
      <div className="app">
        <div className="app__years">
            // Nella render del pezzo html quando devo inserire codice in javascript
           // lo racchiudo tra parentesi graffe
            Object.keys(DATA).map(this.renderYearbuttons.bind(this)) // ogni metodo deve avere un '.bind(this)'
  <App />,