.htaccess appending URL Slugs with the anchor tags

I am creating a blog in Core PHP to get a better understand of the core functionalities of CMS. However, I am facing a challenge in the menu when I am displaying a single post.

I am using the below `.htaccess` code

# code to make pretty URLS | we're using this code to achieve /category/slug
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)/([\w-]+)/([\w-]+)$ app/post.php?&category=$2&slug=$3 [L,QSA]
RewriteRule ^(.+)/([\w-]+)$ app/post.php?category=$2 [L]

The above code will convert `www.example.com/post.php?category=some&slug=title-ti` to `www.example.com/some/title-ti`

Now what's happening is when i am on the index page i am dynamically generating menu. So the menu are as per the slugs.

`Technology
- usage-tips
- overview
`

the above menu URLs will be like `www.example.com/technology`, `www.example.com/usage-tips', 'www.example.com/overview'

but when I open single post page

the URL that I have is `www.example.com/technology/demo-post`

and the Menu URL's that I get is

the above menu URLs will be like `www.example.com/technology/technology`, `www.example.com/technology/usage-tips', 'www.example.com/technology/overview' and more going into it is like an endless loop.

If I inspect the element it's `www.example.com/usage-tips` and so on, but when I am clicking or hovering the links then I am redirected to `www.example.com/technology/usage-tips` links

What's going on is there an error with my php code or the `.htaccess` code

following is my dynamic header code

$query = ' SELECT id, name, slug FROM categories WHERE status = 1 AND parent_id = "'.$parent_id.'" ORDER BY priority ASC ';
$connection = $this->establish_connection();
$data = $connection->query($query);
$connection->close();
if($data->num_rows > 0)
{
$putclass = $menu = "";
while($row = $data->fetch_assoc())
{
if($arrow_status)
{ $putclass = ""; }
else
{ $putclass = "drop"; }

$menu .= '<li class='.$putclass.'><a href="'.$row["slug"].'">'.$row['name'].'</a>';
$menu .= '<ul class="dropdown">'.$this->menu($row["id"], true).'</ul>';
$menu .= '</li>';
}

return $menu;
}

This is my post.php code

<?php
// print_r($_GET);
?>
<?php
if(isset($_GET['category']) && isset($_GET['slug']))
{
?>
//some content if both are set
<?php
}

elseif(isset($_GET['category']) && !isset($_GET['slug']))
{
?>
//some content if only category is set
<?php
}
?>

You want to be using `absolute-path reference` this way the browser will start from the root of your site, rather than the current directory. To use that start the `href` with a leading `/`.

$menu .= '<li class='.$putclass.'><a href="/'.$row["slug"].'">'.$row['name'].'</a>';