NikLP

<?php
// Changes the language switcher block to use country codes instead of long format country names
// So if the site was in English/Italian, the original switcher would show (at D9 iirc):
// English - Italian, and this code makes it into EN - IT (lack of correct formatting notwithstanding)
// This could easily be adapted to show flags etc instead I imagine.

/**
 * Implements hook_preprocess_block().
 */
function mytheme_preprocess_block(&$variables) {

NikLP

function customtheme_preprocess_html(&$variables) {
    $variables['#attached']['html_head'][] = [
        [
        '#type' => 'html_tag',
        '#tag' => 'style',
        '#value' => 'custom-class { background: red; }'
        ],
        'my-custom-theme'
    ];
}

NikLP

.view-VIEWNAME .form--inline .form-item {
  display: inline;
  float: none;
}
 
.view-VIEWNAME .form--inline .form-actions {
  display: inline-block;
}

NikLP

<div{{ attributes.addClass('container') }}>
  {% for item in items %}
    {# NB! notation: loop.index is 1 start, loop.index0 is zero start #}
    <div class="row {{ loop.index0 is odd ? 'zebra-odd' : 'zebra-even' }}">
      <div{{ item.attributes }}>{{ item.content }}</div>
    </div>
  {% endfor %}
</div>

NikLP

.view-VIEWNAME td .dropbutton-multiple {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 0 !important;
  margin: 0 !important;
}

NikLP

/**
 * Provides suggestions for different parts, so that blocks are properly loaded
 *
 * @see hook_theme_suggestions_alter()
 *
 * @param array $suggestions
 * @param array $variables
 * @param string $hook
 */

NikLP

{% extends "paragraph.html.twig" %}
{% block paragraph %}
  <div{{ attributes.addClass('panel-group') }} id="accordion-{{ paragraph.id() }}" role="tablist">
    {% for field in content %}
      {% set field_instance_items = [] %}
      {% for key, field_instance in field if key|first != '#' %}
        {% set field_instance_items = field_instance_items|merge([field_instance]) %}
      {% endfor %}

      {% if field_instance_items is not empty %}

NikLP

/**
 * Implements hook_theme_suggestions_HOOK_alter().
 * Courtesy @nicrodgers
 */
function MYTHEME_theme_suggestions_block_alter(array &$suggestions, array $variables) {
  if (isset($variables['elements']['content']['#block_content'])) {
    $block_content = $variables['elements']['content']['#block_content'];
    $suggestions[] = 'block__' . $block_content->bundle();
  }

NikLP

// paragraph text field actual text
{{ paragraph.field_title.value }}

// paragraph link field uri - internal:/ style (useless?)
{{ paragraph.field_link.0.uri }}

// content has this value - is processed, not validated (good in some cases)
{{ content.field_link[0]['#url'] }}

// paragraph image field uri 

NikLP

{# for a generic answer to this problem, see:
http://stackoverflow.com/questions/19836567/bootstrap-3-multi-column-within-a-single-ul-not-floating-properly
Note that this example has been tailored to a single level menu of plain links; modify a copy of the core 
menu.html.twig with the changes below to keep your menu as per core.
#}
{{ menus.menu_links(items, attributes, 0) }}
{% if items %}
  {%
    set menu_classes = [
      'list-unstyled row',