header.php <?php session_start (); define ( 'BASEURL' , 'http://127.0.0.1:8000/petshopqu' ); ? > <! doctype html > < html lang = "en" > < head > < meta charset = "utf-8" > < meta name = "viewport" content = "width=device-width, initial-scale=1" > < title > PetshopQu </ title > < link href = "https://cdn.jsdelivr.net/npm/bootstrap@5.2.0-beta1/dist/css/bootstrap.min.css" rel = "stylesheet" integrity = "sha384-0evHe/X+R7YkIZDRvuzKMRqM+OrBnVFBL6DOitfPri4tjfHxaWutUpFmBp4vmVor" crossorigin = "anonymous" > < link rel = "stylesheet" href = "https://cdn.jsdelivr.net/npm/bootstrap-icons@1.8.3/font/bootstrap-icons.css" > </ head > < body > < nav class = "navbar navbar-expand-lg bg-black navbar-dark" > < div class = "container" >...