Fix UI on mobile view (#25315)

Various fixes to pages or elements which were looking ugly on mobile.
<details>
<summary>Screenshots</summary>

![Bildschirmfoto vom 2023-06-17
20-38-41](30b5d3ce-df3b-43eb-a4c2-c3790667fb9d)
![Bildschirmfoto vom 2023-06-17
20-39-27](27c07b25-3602-4fb2-b34d-d5e875e054e9)
![Bildschirmfoto vom 2023-06-17
20-41-27](dacdbb4e-e3dd-4b94-abf0-c68e3d64bd3b)
![Bildschirmfoto vom 2023-06-17
20-41-48](72432c35-7c4a-4c7f-a767-3562f26a5c14)
![Bildschirmfoto vom 2023-06-17
20-42-37](737c26ed-1910-4467-98ef-e8769bbbe6f0)
![Bildschirmfoto vom 2023-06-17
20-42-52](1813b4bc-43c0-4912-8acb-5d799c090bf3)
![Bildschirmfoto vom 2023-06-17
20-43-06](136466e8-34e5-419d-97ec-5202ff819fd2)
![Bildschirmfoto vom 2023-06-17
20-43-42](59270bb2-d661-4a84-8504-3e50f771f767)
![Bildschirmfoto vom 2023-06-17
20-44-44](494e274d-3771-4141-9419-0a4bbd8b7f64)

</details>

Co-authored by @silverwind

---------

Co-authored-by: silverwind <me@silverwind.io>

templates/repo/empty.tmpl

@@ -26,7 +26,7 @@
 						<div class="item">
 							<h3>{{.locale.Tr "repo.clone_this_repo"}} <small>{{.locale.Tr "repo.clone_helper" "http://git-scm.com/book/en/Git-Basics-Getting-a-Git-Repository" | Str2html}}</small></h3>
 
-							<div class="gt-df">
+							<div class="repo-button-row">
 								{{if and .CanWriteCode (not .Repository.IsArchived)}}
 									<a class="ui small button" href="{{.RepoLink}}/_new/{{.BranchName | PathEscapeSegments}}/">
 										{{.locale.Tr "repo.editor.new_file"}}
@@ -44,7 +44,7 @@
 						</div>
 
 						{{if not .Repository.IsArchived}}
-							<div class="ui divider"></div>
+							<div class="ui divider gt-my-0"></div>
 
 							<div class="item">
 								<h3>{{.locale.Tr "repo.create_new_repo_command"}}</h3>