app/pages/catalogo.php

<?php include_once "../inc/header.php"; ?>

<div class="container-fluid d-flex justify-content-center my-3">
    <form action="compras.php" method="GET" style="max-width: 600px;" class="container-sm rounded p-3">
        <h1 class="text-center mb-4">Catalogo de articulos</h1>
        <div class="mb-3">
            <label for="articulo" class="form-label">Articulo</label>
            <select id="articulo" class="form-select" name="articulo" aria-label="Default select example">
                <option selected value="zapato">Zapatos</option>
                <option value="camisa">Camisa</option>
                <option value="calcetin">Calcetines</option>
                <option value="lentes">Lentes</option>
            </select>
            <div id="emailHelp" class="form-text">Tu aritulo favorito</div>
        </div>

        <div class="mb-3">
            <label for="cantidad" class="form-label">Cantidad</label>
            <input type="number" name="cantidad" class="form-control" id="cantidad">
        </div>
        <div class="mb-3">
            <label class="form-label" for="precio">Precio</label>
            <input type="number" name="precio" class="form-control" id="precio">
        </div>
        <div class="mb-3">
            <label class="form-label" for="color">Color</label>
            <input type="color" name="color" class="form-control" id="color">
        </div>
        <button type="submit" class="btn btn-primary w-100 mt-2">Submit</button>
    </form>
</div>

<?php include_once "../inc/footer.php"; ?>