rework modal overlay

build/scss/_modals.scss

@@ -5,15 +5,19 @@
 // Overlay
 .modal-dialog {
   .overlay {
-    background-color: $black;
-    display: block;
-    height: 100%;
-    left: 0;
-    opacity: .7;
+    display: flex;
     position: absolute;
+    left: 0;
     top: 0;
-    width: 100%;
+    bottom: 0;
+    right: 0;
+    margin: -$modal-content-border-width;
     z-index: ($zindex-modal + 2);
+    justify-content: center;
+    align-items: center;
+    background-color: rgba($black, .7);
+    color: darken($gray-600, 2.5%);
+    @include border-radius($modal-content-border-radius);
   }
 }
 

pages/UI/modals.html

@@ -1046,7 +1046,7 @@
       <div class="modal fade" id="modal-overlay">
         <div class="modal-dialog">
           <div class="modal-content">
-            <div class="overlay d-flex justify-content-center align-items-center">
+            <div class="overlay">
                 <i class="fas fa-2x fa-sync fa-spin"></i>
             </div>
             <div class="modal-header">