index.html

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <link rel="stylesheet" href="assets/style.css">
        <title>Churrascômetro</title>
    </head>
    <body>
        
        <div class="container">
            <h1>Churrascômetro</h1>
            <input id="adultos" type="number" name="adultos" placeholder="Adultos" >
            <input id="criancas" type="number" name="criancas" placeholder="Crianças" >
            <input id="duracao" type="number" name="duracao" placeholder="Duração (em horas)" >
            <button onclick="calcular()">Calcular</button>

        <div id="resultado">

        </div>

        </div>

        <script src="assets/script.js"></script>
    </body>
</html>