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

const AlertCircleIcon = props => (
  <svg
    width={24}
    height={24}
    viewBox="0 0 24 24"
    fill="none"
    stroke="currentColor"
    strokeWidth={2}
    strokeLinecap="round"
    strokeLinejoin="round"
    {...props}
  >
    <circle cx={12} cy={12} r={10} />
    <line x1={12} y1={8} x2={12} y2={12} />
    <line x1={12} y1={16} x2={12} y2={16} />
  </svg>
);

ReactDOM.render(<AlertCircleIcon />, document.querySelector("#app"))