body {
  font-family: Arial, sans-serif;
  background: #f5f5f5;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

.container {
  background: white;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
  width: 350px;
}

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

.input-container {
  display: flex;
  margin-bottom: 20px;
}

#taskInput {
  flex: 1;
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 8px 0 0 8px;
  outline: none;
}

#addTaskBtn {
  padding: 10px;
  border: none;
  background: #4CAF50;
  color: white;
  border-radius: 0 8px 8px 0;
  cursor: pointer;
}

#addTaskBtn:hover {
  background: #45a049;
}

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

li {
  background: #fafafa;
  padding: 10px;
  border-radius: 6px;
  margin-bottom: 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

li.completed {
  text-decoration: line-through;
  color: #777;
}