styles.css
body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f9;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.container {
  background: white;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  max-width: 400px;
  width: 100%;
}

h1 {
  text-align: center;
  color: #333;
}

form {
  display: flex;
  justify-content: space-between;
  margin-bottom: 1rem;
}

input[type="text"] {
  flex: 1;
  padding: 0.5rem;
  font-size: 1rem;
  border-radius: 4px;
  border: 1px solid #ddd;
  margin-right: 0.5rem;
}

button {
  padding: 0.5rem 1rem;
  font-size: 1rem;
  border: none;
  border-radius: 4px;
  background-color: #007bff;
  color: white;
  cursor: pointer;
  transition: background-color 0.3s;
}

button:hover {
  background-color: #0056b3;
}

ul {
  list-style: none;
  padding: 0;
}

li {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem;
  border-bottom: 1px solid #ddd;
}

li:last-child {
  border-bottom: none;
}

li.completed {
  text-decoration: line-through;
  color: #888;
}

li button {
  background: transparent;
  border: none;
  color: red;
  cursor: pointer;
}