index.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Odd or Even</title>
    <link rel="stylesheet" href="style.css">
</head>

<body>

    <!-- Header Section -->
    <header>
        <nav>
            <a href="#" class="logo">Odd Or Even</a>
            <ol>
                <a href="#">Home</a>
                <a href="#">About</a>
                <a href="#">Services</a>
            </ol>
        </nav>
    </header>

    <!-- Main Section -->
    <main>
        <h1>Let's Check Your Number!</h1>
        <form class="input">
            <div class="input-group">
                <input type="number" class="inputElem" required autofocus />
                <label for="inputElem">Enter Number</label>
            </div>
            <div class="button submitParentElem" style="display: none;">
                <button type="submit" class="submitBtn">Check</button>
            </div>
        </form>
        <h2 class="resultOfNum"></h2>
    </main>

    <script src="script.js" defer></script>
</body>

</html>