How to customize the /node/add page ?

On Drupal 8, there is a page on /node/add. I want to customize this page by replacing the links with buttons, but I have not found a template to do that.

I have also enabled the debug mode, but there is no template suggestion.

How do I customize the page ?

<div role="main" class="main-container container js-quickedit-main-content">
<div class="row">

<div class="col-xs-12 col-sm-12 col-md-12 col-lg-12" role="heading">
<div class="region region-header">

<section class="col-xs-12 col-sm-12 col-md-12 col-lg-12">
<a id="main-content"></a>
<div class="region region-content">
<h1 class="page-header">Ajouter du contenu</h1>
<dt><a href="/node/add/annonce">Annonce</a></dt>
<dt><a href="/node/add/article">Article</a></dt>
<dt><a href="/node/add/discussion">Discussion</a></dt>
<dt><a href="/node/add/recette">Recette</a></dt>



Drupal version: