React

HTML

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

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#app {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  transition: all 0.2s;
}

li {
  margin: 8px 0;
}

h2 {
  font-weight: bold;
  margin-bottom: 15px;
}

.done {
  color: rgba(0, 0, 0, 0.3);
  text-decoration: line-through;
}

input {
  margin-right: 5px;
}

React

ReactDOM.render((
<div className='container' style={{position: 'relative', paddingTop: '100%'}}>
  <iframe
    frameBorder='0'
    scrolling='no'
    allowFullScreen={true}
    style={{position: 'absolute', top: '0', left: '0', height: 'auto', width: '100%'}}
    src='https://twitter.com/ABC/status/1264541688862838785' />
</div>
), document.querySelector("#app"))