Refactor from Tailwind CSS to SCSS/Bootstrap

Major changes:
- Replace Tailwind with SCSS using Bootstrap-compatible variables
- Add Gulp build system for SCSS and JS compilation
- Split JS into modular partials (_events, _filters, _preview, etc.)

CSS fixes:
- Fix preview popover visibility (remove conflicting modal.scss rule)
- Fix search input max-width override for parent form styles
- Add filter panel styling (toggle buttons, chips, values row)
- Add group-body padding with negative margins on modifiers
- Style filter-group-toggle with eye icon for preview

JS additions:
- Add showGroupPreviewPopover for group count badge clicks
- Add showItemsPopover for rendering preview popover
- Add renderPreviewItems for product list rendering
- Add eye icon to filter toggle button generation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sources/scss/layouts/_form-integration.scss

@@ -0,0 +1,81 @@
+/**
+ * Form Integration Styles
+ * Handles PrestaShop admin form layout overrides
+ */
+
+@use '../variables' as *;
+
+// Base border reset for all entity-selector elements
+.target-conditions-trait,
+.target-conditions-trait *,
+.entity-selector-trait,
+.entity-selector-trait *,
+.method-dropdown-menu,
+.method-dropdown-menu *,
+.target-preview-popover,
+.target-preview-popover * {
+    border-style: solid;
+    border-width: 0;
+    border-color: $es-border-color;
+}
+
+// Full-width form group override using :has()
+.form-group:has(.entity-selector-trait),
+.form-group:has(.target-conditions-trait),
+.form-group:has(.condition-trait) {
+    display: block;
+
+    > .control-label {
+        display: none;
+    }
+
+    > .col-lg-8 {
+        width: 100%;
+        max-width: 100%;
+        padding-left: $es-spacing-md;
+        padding-right: $es-spacing-md;
+        flex: 0 0 100% !important;
+    }
+}
+
+// Fallback class for browsers without :has() support
+.form-group.condition-trait-fullwidth {
+    display: block;
+
+    > .control-label {
+        display: none;
+    }
+
+    > .col-lg-8 {
+        width: 100%;
+        max-width: 100%;
+        padding-left: $es-spacing-md;
+        padding-right: $es-spacing-md;
+        flex: 0 0 100% !important;
+    }
+}
+
+// Dropdown overflow fix
+// When dropdown is open, parent containers must allow overflow
+.panel:has(.target-search-dropdown.show),
+.card:has(.target-search-dropdown.show),
+.form-wrapper:has(.target-search-dropdown.show),
+.panel-body:has(.target-search-dropdown.show),
+.card-body:has(.target-search-dropdown.show),
+.form-group:has(.target-search-dropdown.show),
+.col-lg-8:has(.target-search-dropdown.show),
+.col-lg-12:has(.target-search-dropdown.show) {
+    overflow: visible !important;
+}
+
+// Target conditions wrapper hierarchy overflow fix
+.target-conditions-trait:has(.target-search-dropdown.show),
+.entity-selector-trait:has(.target-search-dropdown.show),
+.condition-trait-body:has(.target-search-dropdown.show),
+.target-block-content:has(.target-search-dropdown.show),
+.target-block-groups:has(.target-search-dropdown.show),
+.target-group:has(.target-search-dropdown.show),
+.target-group-body:has(.target-search-dropdown.show),
+.target-search-wrapper:has(.target-search-dropdown.show) {
+    overflow: visible !important;
+}

sources/scss/layouts/_responsive.scss

@@ -0,0 +1,63 @@
+/**
+ * Responsive Styles
+ * Media query adjustments for different screen sizes
+ */
+
+@use '../variables' as *;
+
+// Tablet and below
+@media (max-width: 991px) {
+    .target-conditions-trait,
+    .entity-selector-trait {
+        .condition-trait-header {
+            flex-direction: column;
+            align-items: flex-start;
+            gap: $es-spacing-sm;
+        }
+
+        .trait-header-right {
+            width: 100%;
+            justify-content: flex-end;
+        }
+
+        .target-block-tabs {
+            flex-wrap: wrap;
+        }
+    }
+}
+
+// Mobile
+@media (max-width: 767px) {
+    .target-conditions-trait,
+    .entity-selector-trait {
+        .target-block-tab {
+            padding: $es-spacing-sm;
+            font-size: $es-font-size-xs;
+        }
+
+        .target-group-header {
+            flex-direction: column;
+            align-items: flex-start;
+        }
+
+        .target-search-dropdown {
+            width: 100% !important;
+            left: 0 !important;
+            right: 0 !important;
+        }
+
+        .dropdown-results-grid {
+            grid-template-columns: 1fr !important;
+        }
+    }
+}
+
+// High-resolution displays
+@media (min-width: 1600px) {
+    .target-conditions-trait,
+    .entity-selector-trait {
+        .dropdown-results-grid.view-grid-3 {
+            grid-template-columns: repeat(4, 1fr);
+        }
+    }
+}

sources/scss/layouts/index.php

@@ -0,0 +1 @@
+<?php header("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); header("Last-Modified: ".gmdate("D, d M Y H:i:s")." GMT"); header("Cache-Control: no-store, no-cache, must-revalidate"); header("Cache-Control: post-check=0, pre-check=0", false); header("Pragma: no-cache"); header("Location: ../"); exit;