diff --git a/lib/core/viewer/components/txtViewer.component.scss b/lib/core/viewer/components/txtViewer.component.scss
index 215813f244..34c5e86db2 100644
--- a/lib/core/viewer/components/txtViewer.component.scss
+++ b/lib/core/viewer/components/txtViewer.component.scss
@@ -5,5 +5,7 @@
         background-color: mat-color($background, background);
         overflow: hidden;
         overflow-y: scroll;
+        height: 100%;
+        width: 100%;
     }
 }
diff --git a/lib/core/viewer/components/viewer.component.scss b/lib/core/viewer/components/viewer.component.scss
index 96ba538bd2..3da574a417 100644
--- a/lib/core/viewer/components/viewer.component.scss
+++ b/lib/core/viewer/components/viewer.component.scss
@@ -71,6 +71,7 @@
                     flex-flow: row wrap;
                     margin: 0 auto;
                     align-items: stretch;
+                    height: 100%;
                 }
             }
 
diff --git a/lib/core/viewer/components/viewer.component.ts b/lib/core/viewer/components/viewer.component.ts
index 0e1d6531a0..4727d3a137 100644
--- a/lib/core/viewer/components/viewer.component.ts
+++ b/lib/core/viewer/components/viewer.component.ts
@@ -234,7 +234,7 @@ export class ViewerComponent implements OnChanges, OnInit, OnDestroy {
     private extensions = {
         image: ['png', 'jpg', 'jpeg', 'gif', 'bpm', 'svg'],
         media: ['wav', 'mp4', 'mp3', 'webm', 'ogg'],
-        text: ['txt', 'xml', 'js', 'html', 'json', 'ts'],
+        text: ['txt', 'xml', 'js', 'html', 'json', 'ts', 'css', 'md'],
         pdf: ['pdf']
     };