ABooooo

// compare with autogenerated code

<div class="boxContent" style="background-image: url(

        <f:if condition="{data_item.tx_mask_bgimage}">
        <f:for each="{data_item.tx_mask_bgimage}" as="file">
          <f:uri.image src="{file.publicUrl}" />
        </f:for>
        </f:if>

ABooooo

Since TYPO3 8LTS

Since version 8 TYPO3 uses the standalone version of fluid, that was heavily developed and got tons of new features like elseif:

<f:if condition="{var} == 'something'">
    <f:then>do something</f:then>
    <f:else if="{other-var} == 'something else'">do something else</f:else>
    <f:else>do the other thing</f:else>
</f:if>
In addition there is support for syntax like this:

ABooooo

In Extension Manager (EM) find the RealURL and set option Automatic configuration file format to PHP source (slow!) (with automatic conf still enabled!)
Remove the file typo3conf/realurl_autoconf.php (as far as I remember), clear all caches and refresh the main page, the autoconf file will be recreated in unserialized version.
Rename the file to typo3conf/realurl_conf.php, go to EM again and uncheck the automatic configuration option.
After clearing the caches and you'll be switched to manual config built from the automatic one.

ABooooo

1. https://docs.acquia.com/lightning/install/local/
2. https://gist.github.com/criscom/d973ea5e4328bf8aab39857ecf93b075

#Install lightning
composer create-project acquia/lightning-project MY_PROJECT --no-interaction
open with browser MY_PROJECT/docroot
install Drupal

#error execution time
https://www.drupal.org/forum/support/installing-drupal/2014-01-22/maximum-execution-time-of-30-seconds-exceeded-in-drupal

ABooooo

https://gist.github.com/Metaviolet/682c8d3b05a3a01fd598

//First declare breakpoints
$breakpoints: (
  'small':  767px,
  'medium': 992px,
  'large':  1200px
) !default;

/// Mixin to manage responsive breakpoints

ABooooo

<?php echo get_template_directory_uri(); ?>

ABooooo

https://code.tutsplus.com/tutorials/dynamically-adding-four-footer-widget-areas--cms-22168

ABooooo

// register sidebar in functions
function alle_sprachen_widgets_init() {
	register_sidebar( array(
		'name'          => esc_html__( 'Sidebar', 'alle_sprachen' ),
		'id'            => 'sidebar-1',
		'description'   => esc_html__( 'Add widgets here.', 'alle_sprachen' ),
		'before_widget' => '<section id="%1$s" class="widget %2$s">',
		'after_widget'  => '</section>',
		'before_title'  => '<h2 class="widget-title">',
		'after_title'   => '</h2>',

ABooooo

// Register Sidebar
function alle_sprachen_widgets_init() {
	
	register_sidebar( array(
        'name'          => esc_html__( 'Header-Hero', 'alle_sprachen' ),
        'id'            => 'header_hero',
        'description'   => esc_html__( 'Add widgets here.', 'alle_sprachen' ),
        'before_widget' => '<section id="%1$s" class="widget %2$s">',
        'after_widget'  => '</section>',
        'before_title'  => '<h2 class="widget-title">',

ABooooo

// get page ID with objct post
$custompageid = get_field('anfrageseite_id', 'option'); // 'options' is standard value!!!