body {
  font-family: -apple-system, sans-serif;
  background: #f4f4f5;
  display: flex;
  justify-content: center;
  padding-top: 60px;
}
.container {
  background: #fff;
  padding: 24px;
  border-radius: 8px;
  width: 360px;
  box-shadow: 0 1px 4px rgba(0,0,0,0.1);
}
h1 { margin-top: 0; }
form { display: flex; gap: 8px; margin-bottom: 16px; }
input { flex: 1; padding: 8px; border: 1px solid #ccc; border-radius: 4px; }
button { padding: 8px 12px; border: none; background: #2563eb; color: white; border-radius: 4px; cursor: pointer; }
ul { list-style: none; padding: 0; margin: 0; }
li { display: flex; align-items: center; gap: 8px; padding: 8px 0; border-bottom: 1px solid #eee; }
li.done span { text-decoration: line-through; color: #999; }
li span { flex: 1; cursor: pointer; }
li button { background: #ef4444; }