index.html

<!doctype html>
<html lang="ru">
<head>
	<meta charset="UTF-8">
	<meta name="viewport"
				content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<title>ToDo</title>

	<link rel="stylesheet" type="text/css" href="css/normalize.css">
	<link rel="stylesheet" type="text/css" href="css/style.css">
</head>
<body>

<header class="header">
	<form class="todo-control">
		<label><input class="header-input" type="text" placeholder="Какие планы?"></label>
		<button class="header-button" id="add"></button>
	</form>
</header>

<div class="todo-container">

	<ul class="todo todo-list" id="todo">
	
	</ul>
	<ul class="todo todo-completed" id="completed">
		
	</ul>
</div>

<script src="./js/script.js"></script>
</body>
</html>