added backup apis and tests

ui/src/scss/_base.scss

@@ -511,9 +511,10 @@ a,
 .thumb {
     --thumbSize: 40px;
 
-    flex-shrink: 0;
-    position: relative;
     display: inline-flex;
+    vertical-align: top;
+    position: relative;
+    flex-shrink: 0;
     align-items: center;
     justify-content: center;
     line-height: 1;
@@ -772,7 +773,7 @@ a.thumb:not(.thumb-active) {
             align-items: center;
             margin: -1px -5px -1px 0;
             &.nonintrusive {
-                @include hide();
+                opacity: 0;
                 transform: translateX(5px);
                 transition: transform var(--baseAnimationSpeed),
                             opacity var(--baseAnimationSpeed),
@@ -780,9 +781,12 @@ a.thumb:not(.thumb-active) {
             }
         }
         &:hover,
+        &:focus-visible,
+        &:focus-within,
         &:active {
+            background: var(--bodyColor);
             .actions.nonintrusive {
-                @include show();
+                opacity: 1;
                 transform: translateX(0);
             }
         }
@@ -807,13 +811,28 @@ a.thumb:not(.thumb-active) {
         }
     }
 
+    .list-item-placeholder {
+        color: var(--txtHintColor);
+    }
+
     .list-item-btn {
         padding: 5px;
         min-height: auto;
     }
 
+    .list-item-placeholder,
+    .list-item-btn {
+        &:hover,
+        &:focus-visible,
+        &:focus-within,
+        &:active {
+            background: none;
+        }
+    }
+
     &.list-compact {
         .list-item {
+            gap: 10px;
             min-height: 40px;
         }
     }