无法将css应用于bootstrap导航栏

I'm trying to add custom styles to navigation and body but the styles aren't showing in my home page but it's showing in another page I'm not getting it any one can help me out with solution where I'm messing around

index.php

<?php include 'include/css.php';?>
<?php $page = 'home';include 'include/navbar.php';?>

<?php include 'include/scripts.php';?>

Screenshot of browser for index.php

css.php

<html lang="en">
    <head>
        <title>Bootstrap 4 Example</title>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" >
        <link rel="stylesheet" href="../css/style.css">
    </head>
    <body>

Screenshot of browser for /include/css.php

style.css

body{
    background-color: aqua;!important
}
.navbar-nav > li > a {
    color: #ffffff;
}

i am attaching github link please download files upload in your local server and kindly find the error

you can download files here

Try this one.

body{
   background-color: aqua !important;
}
.navbar-nav a {
    color: #ffffff !important;
}

maybe you have a path issue for <link rel="stylesheet" href="../css/style.css"> check your directory for home page and other pages.