Minor css improvements

src/css/ingame_hud/dialogs.scss

@@ -11,6 +11,16 @@
     align-items: center;
     justify-content: center;
 
+    @include InlineAnimation(0.12s ease-in-out) {
+        0% {
+            background-color: transparent;
+            opacity: 0.5;
+        }
+        100% {
+            background-color: $modalDialogBg;
+        }
+    }
+
     &.visible {
         .dialogInner {
             opacity: 1;

src/css/ingame_hud/game_menu.scss

@@ -1,7 +1,6 @@
 #ingame_HUD_GameMenu {
     position: absolute;
     top: 0;
-    left: calc(50% - #{D(50px)});
     right: 0;
     display: flex;
     grid-auto-flow: column;
@@ -12,6 +11,7 @@
         flex-grow: 1;
         @include S(padding, 5px, 4px);
         justify-content: flex-end;
+        @include S(margin-left, 20px);
 
         > .button {
             @include S(width, 30px);