Add back the dark header

src/components/AppHeader/AppHeader.css

@@ -4,6 +4,7 @@
   padding: 8px 24px;
   height: auto;
   background-color: var(--backgroundAltColor);
+  color: var(--defaultColorLight);
 }
 
 /* Gross stuff below, React Toolbox hacks */
@@ -22,7 +23,7 @@
 .leftIcon span {
   /* stylelint-disable */
 
-  color: var(--textColor) !important;
+  color: var(--defaultColorLight) !important;
   font-size: 24px !important;
 
   /* stylelint-enable */

src/components/UI/theme.css

@@ -16,7 +16,7 @@
   --dropShadow: 0 2px 4px 0 rgba(19, 39, 48, .12);
   --topmostZindex: 99999;
   --foregroundAltColor: #fff;
-  --backgroundAltColor: #313d3e;
+  --backgroundAltColor: #232528;
   --textFieldBorderColor: #e7e7e7;
   --highlightFGColor: #fff;
   --highlightBGColor: #3ab7a5;