index.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Todo</title>
    <link rel="stylesheet" href="css/index.css">
</head>

<body>
    <div class="todo">
        <div class="todo__encabezado">
            <h1>TODO LIST 📔🌠🌠</h1>
            <button class="btn-delete" id="add-task">Delete all completed</button>
        </div>
        <div class="todo__body">
            <div class="body__search">
                <input placeholder="Add a new TODO" type="text" id="search-box">
            </div>
            <div class="body__task">
                <ul id="list">
                </ul>
            </div>
        </div>
        <div class="warning hidde" id="warning-alert">
            <p>All completed task has been deleted</p>
        </div>
    </div>
    <script src="js/todo.js"></script>
</body>

</html>