wagtail_bakerydemo/bakerydemo/templates/wagtailcore/shared/block_preview.html

{% extends "wagtailcore/shared/block_preview.html" %}
{% load static %}

{% block content %}
    {# Add a wrapper so we can add padding with our own CSS class #}
    <div class="block-preview">
        {{ block.super }}
    </div>
{% endblock %}

{% block css %}
    {{ block.super }}
    <link rel="stylesheet" href="{% static 'css/bootstrap.min.css' %}">
    <link rel="stylesheet" href="{% static 'css/font-marcellus.css' %}">
    <link rel="stylesheet" href="{% static 'css/main.css' %}">
{% endblock %}

{% block js %}
    {# None of our blocks need JavaScript at the moment. #}
    {{ block.super }}
{% endblock %}