body {
  font-family: Arial, sans-serif;
  background: #f2f2f2;
  display: flex;
  justify-content: center;
  padding-top: 50px;
}

.container {
  background: #fff;
  padding: 20px 30px;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
  width: 300px;
}

h1 {
  text-align: center;
  margin-bottom: 20px;
}

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

input[type="text"] {
  flex: 1;
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 4px;
}

button {
  padding: 10px;
  border: none;
  background: #007bff;
  color: white;
  border-radius: 4px;
  cursor: pointer;
}

button:hover {
  background: #0056b3;
}

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

li {
  padding: 10px;
  background: #eee;
  margin-bottom: 10px;
  display: flex;
  justify-content: space-between;
  border-radius: 4px;
}

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

li button {
  background: red;
  border: none;
  color: white;
  padding: 5px 8px;
  border-radius: 4px;
  cursor: pointer;
}