Merge pull request #19734 from calixteman/bug1952563

[Editor] Add a border to the undo button in the snackbar in order to make a contrast (bug 1952563)

web/message_bar.css

@@ -139,6 +139,8 @@
   --undo-button-bg-color-hover: rgb(21 20 26 / 0.14);
   --undo-button-bg-color-active: rgb(21 20 26 / 0.21);
 
+  --undo-button-border: 1px solid #0060df;
+
   --undo-button-fg-color: var(--message-bar-fg-color);
   --undo-button-fg-color-hover: var(--undo-button-fg-color);
   --undo-button-fg-color-active: var(--undo-button-fg-color);
@@ -153,6 +155,8 @@
     --undo-button-bg-color: rgb(255 255 255 / 0.08);
     --undo-button-bg-color-hover: rgb(255 255 255 / 0.14);
     --undo-button-bg-color-active: rgb(255 255 255 / 0.21);
+
+    --undo-button-border: 1px solid #0df;
   }
 
   @media screen and (forced-colors: active) {
@@ -169,6 +173,8 @@
     --undo-button-fg-color: ButtonFace;
     --undo-button-fg-color-hover: SelectedItemText;
     --undo-button-fg-color-active: SelectedItemText;
+
+    --undo-button-border: none;
   }
 
   position: fixed;
@@ -194,7 +200,7 @@
     font-weight: 590;
     line-height: 19.5px;
     color: var(--undo-button-fg-color);
-    border: none;
+    border: var(--undo-button-border);
     padding: 4px 16px;
     margin-inline-start: 8px;
     height: 32px;