Fix up dark mode nav colors

Also improve select2 text color

app/assets/stylesheets/framework/gitlab_theme.scss

@@ -308,7 +308,6 @@ body {
     );
   }
 
-  &.gl-dark,
   &.ui-light {
     @include gitlab-theme(
       $gray-700,
@@ -391,13 +390,47 @@ body {
   }
 
   &.gl-dark {
-    @include gitlab-theme(
-      $gray-900,
-      $gray-500,
-      $gray-700,
-      $gray-800,
-      $gray-50,
-      $gray-100
-    );
+    .logo-text svg {
+      fill: $gl-text-color;
+    }
+
+    .navbar-gitlab {
+      background-color: $gray-50;
+
+      .navbar-sub-nav,
+      .navbar-nav {
+        li {
+          > a:hover,
+          > a:focus,
+          > button:hover,
+          > button:focus {
+            color: $gl-text-color;
+            background-color: $gray-200;
+          }
+        }
+
+        li.active,
+        li.dropdown.show {
+          > a,
+          > button {
+            color: $gl-text-color;
+            background-color: $gray-200;
+          }
+        }
+      }
+
+      .search {
+        form {
+          background-color: $gray-100;
+          box-shadow: inset 0 0 0 1px $border-color;
+
+          &:active,
+          &:hover {
+            background-color: $gray-100;
+            box-shadow: inset 0 0 0 1px $blue-200;
+          }
+        }
+      }
+    }
   }
 }

app/assets/stylesheets/framework/selects.scss

@@ -12,6 +12,7 @@
 .select2-container.select2-drop-above {
   .select2-choice {
     background: $white;
+    color: $gl-text-color;
     border-color: $input-border;
     height: 34px;
     padding: $gl-vert-padding $gl-input-padding;

app/assets/stylesheets/themes/_dark.scss

@@ -99,7 +99,7 @@ $border-white-normal: $gray-900;
 
 $body-bg: $gray-50;
 $input-bg: $gray-100;
-$input-focus-bg: $gray-50;
+$input-focus-bg: $gray-100;
 $input-color: $gray-900;
 $input-group-addon-bg: $gray-900;