Merge pull request DSpace#4337 from DSpace/backport-3373-to-dspace-8_x

[Port dspace-8_x] Adjust the font size of the 'No thumbnails available' text.

Author: tdonohue

src/styles/_global-styles.scss

@@ -230,15 +230,31 @@ ds-dynamic-form-control-container.d-none {
 }
 
 .thumb-font-2 {
-    .thumbnail-placeholder {
-        font-size: 0.9rem;
-        padding: 0.125rem;
+  .thumbnail-placeholder {
+    @media screen and (max-width: map-get($grid-breakpoints, sm)) {
+      font-size: 0.4rem;
+      padding: 0.1rem;
     }
+    @media screen and (min-width: map-get($grid-breakpoints, sm)) and (max-width: map-get($grid-breakpoints, lg)) {
+        font-size: 0.7rem;
+        padding: 0.1rem;
+    }
+    font-size: 1rem;
+    padding: 0.5rem;
+  }
 }
 
 .thumb-font-3 {
     .thumbnail-placeholder {
-        font-size: 1.25rem;
+        @media screen and (max-width: map-get($grid-breakpoints, sm)) {
+          font-size: 0.4rem;
+          padding: 0.1rem;
+        }
+        @media screen and (min-width: map-get($grid-breakpoints, sm)) and (max-width: map-get($grid-breakpoints, lg)) {
+            font-size: 0.7rem;
+            padding: 0.1rem;
+        }
+        font-size: 1rem;
         padding: 0.5rem;
     }
 }