minor css adjustments

src/components/EntryEditor.css

@@ -12,6 +12,7 @@
   height: 45px;
   border-top: 1px solid #e8eae8;
   padding: 10px 20px;
+  z-index: 10;
 }
 .controlPane {
   width: 50%;

src/components/PreviewPane.css

@@ -1,6 +1,6 @@
 .frame {
   width: 100%;
-  height: 100%;
+  height: 100vh;
   border: none;
   background: #fff;
 }