index.html

<h1 id="header"></h1>

main.dart

import 'dart:html';
import 'dart:convert';

void main() async {
  var raw = await HttpRequest.getString('https://swapi.co/api/people/1');
  var ruke = jsonDecode(raw);
  var $header = querySelector('#header');
  $header.text = ruke["name"];
}

styles.css

body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: absolute;
  width: 100%;
  height: 100%;
  background-color: #303f41;
}

h1 {
  color: #f0f0f0;
  font-family: serif;
}