Style and template tweaks (#13828)

* Style and template tweaks

- Get red and green buttons on arc green closer to base theme
- EasyMDE adjustments, toolbar and focus border
- Fix header on 404 repo page
- Tweaks to frontpage search, add 'Create Repo' button
- Fix misaligned box headers
- Fix pagination on arc-green
- Fix background and footer on explore and repo search

* better fix for header button alignment

* add label hover for reactions

templates/repo/issue/view_title.tmpl

@@ -9,7 +9,7 @@
 			<span id="issue-title">{{RenderIssueTitle .Issue.Title $.RepoLink $.Repository.ComposeMetas}}</span>
 			<span class="index">#{{.Issue.Index}}</span>
 			<div id="edit-title-input" class="ui input" style="display: none">
-				<input value="{{.Issue.Title}}" maxlength="255">
+				<input value="{{.Issue.Title}}" maxlength="255" autocomplete="off">
 			</div>
 		</h1>
 		{{if and (or .HasIssuesOrPullsWritePermission .IsIssuePoster) (not .Repository.IsArchived)}}