<div class="todo-app-container">
    <h1>My Awesome To-Do List</h1>

    <div class="input-area">
      <input type="text" id="todoInput" placeholder="Add a new task...">
      <button id="addButton">Add</button>
    </div>

    <ul id="todoList" class="todo-list">
      </ul>
  </div>

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: #e0f7fa; /* Light Cyan background */
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.todo-app-container {
  background-color: #fff;
  padding: 35px;
  border-radius: 12px;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
  width: 90%;
  max-width: 600px;
  text-align: center;
}

h1 {
  color: #26a69a; /* Teal heading */
  margin-bottom: 30px;
}

.input-area {
  display: flex;
  margin-bottom: 25px;
}

input[type="text"] {
  flex-grow: 1;
  padding: 15px;
  border: 2px solid #b2dfdb; /* Light Teal border */
  border-radius: 8px 0 0 8px;
  font-size: 16px;
  outline: none;
}

input[type="text"]:focus {
  border-color: #26a69a; /* Darker Teal on focus */
  box-shadow: 0 0 5px rgba(38, 166, 154, 0.5);
}

button {
  background-color: #26a69a; /* Teal button */
  color: white;
  padding: 15px 25px;
  border: none;
  border-radius: 0 8px 8px 0;
  font-size: 18px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

button:hover {
  background-color: #00897b; /* Darker Teal on hover */
}

.todo-list {
  list-style: none;
  padding: 0;
}

.todo-list li {
  background-color: #f0f0f0; /* Light gray list item */
  padding: 15px;
  margin-bottom: 10px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: space-between; /* Space between text and button */
}

.todo-list li:nth-child(even) {
  background-color: #e8e8e8; /* Slightly different gray for even items */
}

.todo-list li.completed {
  text-decoration: line-through;
  color: #777;
  background-color: #d3d3d3; /* Lighter gray for completed items */
}

.todo-list li button {
  background-color: #4caf50; /* Green button for "Complete" */
  color: white;
  border-radius: 5px;
  padding: 8px 15px;
  font-size: 14px;
  cursor: pointer;
  border: none;
  transition: background-color 0.3s ease;
}

.todo-list li button:hover {
  background-color: #43a047; /* Darker green on hover */
}

.todo-list li button:focus {
  outline: none; /* Remove default focus outline */
  box-shadow: 0 0 4px rgba(76, 175, 80, 0.7); /* Add a subtle focus shadow */
}

class ToDo {
  constructor(description) {
    this.description = description;
    this.completed = false;
  }

  markComplete() {
    this.completed = true;
    console.log(`"${this.description}" marked as complete!`);
  }
}

class ToDoList {
  constructor() {
    this.todos = [];
  }

  addTodo(description) {
    const newTodo = new ToDo(description);
    this.todos.push(newTodo);
    this.renderTodoList();
  }

  listTodos() {
    return this.todos;
  }

  markTodoComplete(index) {
    if (index >= 0 && index < this.todos.length) {
      this.todos[index].markComplete();
      this.renderTodoList();
    }
  }

  renderTodoList() {
    const todoListElement = document.getElementById('todoList');
    todoListElement.innerHTML = '';
    this.todos.forEach((todo, index) => {
      const listItem = document.createElement('li');
      listItem.textContent = todo.description;

      if (todo.completed) {
        listItem.classList.add('completed');
      }

      const completeButton = document.createElement('button');
      completeButton.textContent = 'Complete';
      completeButton.onclick = () => this.markTodoComplete(index);

      listItem.appendChild(completeButton);
      todoListElement.appendChild(listItem);
    });
  }
}

const myTodoList = new ToDoList();

const addButton = document.getElementById("addButton");
const todoInput = document.getElementById("todoInput");

addButton.addEventListener("click", () => {
  const todoText = todoInput.value.trim();
  if (todoText) {
    myTodoList.addTodo(todoText);
    todoInput.value = "";
  }
});

myTodoList.renderTodoList();