Add "blog" like header image to "default" pages

I'm trying to add the header image feature from the blog list to every "default" pages, but when I add the code, it will not even show the content of the "default.md". It does however show everything but the content generated by default.html.twig. E.g. empty #body DOM.

The theme is Antimatter with this default.html.twig:

{% extends 'partials/base.html.twig' %}

{% block content %}
  {% set default_image = page.media.images|first.grayscale().contrast(20).brightness(-100).colo rize(-35,81,122) %}

    {% if default_image %}
    <div class="flush-top blog-header blog-header-image" style="background-image: url({{ default_image.url }});">
    {% else %}
    <div class="blog-header">
    {% endif %}
        {{ page.title }}
    </div>

    {{ page.content }}
{% endblock %}

Anyone who can help me here?

Can you identify the piece of code that makes the page crash after your edits, instead of showing the original content?

Actualy I just got it working. I used {{ page.title }} when it should've been {{ page.header.title }}.