refactor: preview documents HTML structure for styling

src/QUI/ERP/Accounting/ArticleList.css

@@ -39,7 +39,9 @@ table.articles-article {
 }
 
 .articles-article-pos,
-.articles-article-quantity {
+.articles-article-quantity,
+.articles-article-articleNo,
+.articles-article-vat {
     text-align: center;
     vertical-align: top;
 }

src/QUI/ERP/Output/OutputTemplate.php

@@ -130,9 +130,27 @@ public function getHTML($preview = false)
         $this->Engine->assign($templateData);
         $this->preview = $preview;
 
-        $html = $this->getHTMLHeader().
-                $this->getHTMLBody().
-                $this->getHTMLFooter();
+        $html = '<style>
+    body {
+        display: flex;
+        flex-direction: column;
+        margin: 0;
+        height: 100%;
+    }
+    
+    .quiqqer-erp-output-html-footer {
+        position: relative;
+        margin-top: auto;
+    }
+    
+    .quiqqer-erp-output-footer {
+        position: static !important;
+    }
+</style>';
+
+        $html .= '<div class="quiqqer-erp-output-html-header">'.$this->getHTMLHeader().'</div>';
+        $html .= '<div class="quiqqer-erp-output-html-body">'.$this->getHTMLBody().'</div>';
+        $html .= '<div class="quiqqer-erp-output-html-footer">'.$this->getHTMLFooter().'</div>';
 
         QUI::getLocale()->resetCurrent();