[#1548] added PDF preview

ui/src/scss/_overlay_panel.scss

@@ -210,12 +210,7 @@
     &.full-width-popup {
         width: 100%;
     }
-    &.image-preview {
-        width: auto;
-        min-width: 300px;
-        min-height: 250px;
-        max-width: 70%;
-        max-height: 90%;
+    &.preview {
         .panel-header {
             position: absolute;
             z-index: 99;
@@ -243,12 +238,30 @@
             align-items: center;
             justify-content: center;
         }
+    }
+    &.image-preview {
+        width: auto;
+        min-width: 300px;
+        min-height: 250px;
+        max-width: 70%;
+        max-height: 90%;
         img {
             max-width: 100%;
             border-top-left-radius: var(--baseRadius);
             border-top-right-radius: var(--baseRadius);
         }
     }
+    &.pdf-preview {
+        width: 70%;
+        height: 90%;
+        object {
+            position:absolute;
+            left:0;
+            top:0;
+            width:100%;
+            height:100%;
+        }
+    }
 
     @media (max-width: 900px) {
         .overlay-panel-section {