blog menu links path

Sounds stupid to me but can't figure out how to properly add correct navigation menu links on top of my blog posts.

As the post.php file is located at /blog/post.php, links are going to the root of the blog folder. So i have to add the correct path with ../

Here is my content for my menu. How should i manage to have the correct path ? Moving everything outside the blog folder ?

<ul>
    <li><a href="index.php"><perch:content id="menu-1" type="text" label="Lien menu 1"/></a></li>
    <li><a href="pilates-gym-douce-stretching.php"><perch:content id="menu-2" type="text" label="Lien menu 2"/></a>
        <ul>
            <li><a href="cours-pilates.php"><perch:content id="item-1-sous-menu-1" type="text" label="Lien sous-menu 1"/></a></li>
            <li><a href="cours-gym-douce.php"><perch:content id="item-1-sous-menu-2" type="text" label="Lien sous-menu 2"/></a></li>
            <li><a href="cours-stretching.php"><perch:content id="item-1-sous-menu-3" type="text" label="Lien sous-menu 3"/></a></li>
        </ul>
    </li>
    <li><a href="#"><perch:content id="menu-3" type="text" label="Lien menu 3"/></a>
        <ul>
            <li><a href="reformer-pilates.php"><perch:content id="item-1-sous-menu-4" type="text" label="Lien sous-menu 1"/></a></li>
            <li><a href="cours-gym-douce.php"><perch:content id="item-1-sous-menu-5" type="text" label="Lien sous-menu 2"/></a></li>
        </ul>
    </li>
</ul>