body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
}

.container {
  max-width: 500px;
  margin: 50px auto;
  background: white;
  padding: 20px;
  border-radius: 8px;
}

.input-area {
  display: flex;
  gap: 10px;
}

input {
  flex: 1;
  padding: 8px;
}

button {
  padding: 8px 12px;
  cursor: pointer;
}

ul {
  list-style: none;
  padding: 0;
  margin-top: 20px;
}

li {
  padding: 8px;
  display: flex;
  justify-content: space-between;
  cursor: pointer;
}

.completed {
  text-decoration: line-through;
  opacity: 0.6;
}

li button {
  background: none;
  border: none;
  color: red;
  font-size: 16px;
}