sticky download button so long previews doesn't push buttons down, closes #205

components/previews/OfficePreview.tsx

@@ -12,14 +12,18 @@ const OfficePreview: FunctionComponent<{ file: any }> = ({ file }) => {
   }, [])
 
   return (
-    <>
+    <div>
       <div className="overflow-scroll" ref={docContainer} style={{ maxHeight: '90vh' }}>
-        <Preview url={encodeURIComponent(file['@microsoft.graph.downloadUrl'])} width={docContainerWidth.toString()} height="800" />
+        <Preview
+          url={encodeURIComponent(file['@microsoft.graph.downloadUrl'])}
+          width={docContainerWidth.toString()}
+          height="600"
+        />
       </div>
-      <div className="mt-4">
+      <div className="border-t-gray-200 dark:border-t-gray-700 border-t p-2 sticky bottom-0 left-0 right-0 z-10 bg-white bg-opacity-80 backdrop-blur-md dark:bg-gray-900">
         <DownloadButtonGroup downloadUrl={file['@microsoft.graph.downloadUrl']} />
       </div>
-    </>
+    </div>
   )
 }