Fix Show/hide filetree button on small displays (#27881)

the gt-df's display:flex !important did override the display:none on small displays

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/diff/box.tmpl

@@ -3,7 +3,7 @@
 	<div class="diff-detail-box diff-box">
 		<div class="gt-df gt-ac gt-fw">
 			{{if $showFileTree}}
-				<button class="diff-toggle-file-tree-button gt-df gt-ac not-mobile" data-show-text="{{ctx.Locale.Tr "repo.diff.show_file_tree"}}" data-hide-text="{{ctx.Locale.Tr "repo.diff.hide_file_tree"}}">
+				<button class="diff-toggle-file-tree-button not-mobile btn interact-fg" data-show-text="{{ctx.Locale.Tr "repo.diff.show_file_tree"}}" data-hide-text="{{ctx.Locale.Tr "repo.diff.hide_file_tree"}}">
 					{{/* the icon meaning is reversed here, "octicon-sidebar-collapse" means show the file tree */}}
 					{{svg "octicon-sidebar-collapse" 20 "icon gt-hidden"}}
 					{{svg "octicon-sidebar-expand" 20 "icon gt-hidden"}}
@@ -89,7 +89,7 @@
 	{{end}}
 	<div id="diff-container">
 		{{if $showFileTree}}
-			<div id="diff-file-tree" class="gt-hidden"></div>
+			<div id="diff-file-tree" class="gt-hidden not-mobile"></div>
 			<script>
 				if (diffTreeVisible) document.getElementById('diff-file-tree').classList.remove('gt-hidden');
 			</script>

web_src/css/repo.css

@@ -2743,26 +2743,6 @@ tbody.commit-list {
   overflow-y: auto;
 }
 
-.diff-toggle-file-tree-button {
-  background: none;
-  border: none;
-  user-select: none;
-  color: inherit;
-}
-
-.diff-toggle-file-tree-button:hover {
-  color: var(--color-primary);
-}
-
-@media (max-width: 991.98px) {
-  #diff-file-tree {
-    display: none !important;
-  }
-  .diff-toggle-file-tree-button {
-    display: none !important;
-  }
-}
-
 .ui.message.unicode-escape-prompt {
   margin-bottom: 0;
   border-radius: 0;