Improve accessibility when (re-)viewing files (#24817)

Visually, nothing should have changed.
Changes include
- Convert most `<a [no href]>` to `<button>` when (re-)viewing files:
- `<a [no href]>` are, by HTML definition, not a link and hence cannot
be focused
- `<a class="ui button">` can now be clicked (again?) using
<kbd>Enter</kbd>
- Previously, the installed keypress handler on `.ui.button` elements
disabled it for links somehow
- The `(un)escape file`, the `expand section` and the `expand/collapse
file` buttons can now be focused (and subsequently clicked using only
the keyboard)
- You can now press <kbd>Space</kbd> on a focused `View file` checkbox
to mark the file as viewed.
- previously, this was impossible as this checkbox listened on the wrong
event listener

The `add code comment` button has been left inaccessible for now as it
requires quite a bit of extra logic so that it is unhidden when it is
focused (you can otherwise focus it without seeing it as you are not
hovering on the corresponding line).

---------

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

8 files changed, 80 insertions, 68 deletions

diff --git a/templates/repo/blame.tmpl b/templates/repo/blame.tmpl
index c3e2d56af3..e6bf1cc96f 100644
--- a/templates/repo/blame.tmpl
+++ b/templates/repo/blame.tmpl
@@ -11,8 +11,8 @@
 				{{end}}
 				<a class="ui tiny button" href="{{.RepoLink}}/src/{{.BranchNameSubURL}}/{{.TreePath | PathEscapeSegments}}">{{.locale.Tr "repo.normal_view"}}</a>
 				<a class="ui tiny button" href="{{.RepoLink}}/commits/{{.BranchNameSubURL}}/{{.TreePath | PathEscapeSegments}}">{{.locale.Tr "repo.file_history"}}</a>
-				<a class="ui tiny button unescape-button">{{.locale.Tr "repo.unescape_control_characters"}}</a>
-				<a class="ui tiny button escape-button gt-hidden">{{.locale.Tr "repo.escape_control_characters"}}</a>
+				<button class="ui tiny button unescape-button">{{.locale.Tr "repo.unescape_control_characters"}}</button>
+				<button class="ui tiny button escape-button gt-hidden">{{.locale.Tr "repo.escape_control_characters"}}</button>
 			</div>
 		</div>
 	</h4>
@@ -52,7 +52,7 @@
 							{{if $.EscapeStatus.Escaped}}
 								<td class="lines-escape">
 									{{if $row.EscapeStatus.Escaped}}
-										<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $row "locale" $.locale}}"></a>
+										<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $row "locale" $.locale}}"></button>
 									{{end}}
 								</td>
 							{{end}}
diff --git a/templates/repo/diff/blob_excerpt.tmpl b/templates/repo/diff/blob_excerpt.tmpl
index 7e11b33ba6..ab7abdbd7b 100644
--- a/templates/repo/diff/blob_excerpt.tmpl
+++ b/templates/repo/diff/blob_excerpt.tmpl
@@ -3,28 +3,30 @@
 	<tr class="{{.GetHTMLDiffLineType}}-code nl-{{$k}} ol-{{$k}}">
 		{{if eq .GetType 4}}
 			<td class="lines-num lines-num-old" data-line-num="{{if $line.LeftIdx}}{{$line.LeftIdx}}{{end}}">
+				<div class="gt-df">
 				{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 5)}}
-					<a role="button" class="blob-excerpt" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=down&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
+					<button class="code-expander-button" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=down&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
 						{{svg "octicon-fold-down"}}
-					</a>
+					</button>
 				{{end}}
 				{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 4)}}
-					<a role="button" class="blob-excerpt" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=up&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
+					<button class="code-expander-button" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=up&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
 						{{svg "octicon-fold-up"}}
-					</a>
+					</button>
 				{{end}}
 				{{if eq $line.GetExpandDirection 2}}
-					<a role="button" class="blob-excerpt" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
+					<button class="code-expander-button" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
 						{{svg "octicon-fold"}}
-					</a>
+					</button>
 				{{end}}
+				</div>
 			</td>
 			<td colspan="7" class="lines-code lines-code-old ">{{$inlineDiff := $.section.GetComputedInlineDiffFor $line $.locale}}{{/*
 				*/}}{{template "repo/diff/section_code" dict "diff" $inlineDiff "locale" $.locale}}</td>
 		{{else}}
 			{{$inlineDiff := $.section.GetComputedInlineDiffFor $line $.locale}}
 			<td class="lines-num lines-num-old" data-line-num="{{if $line.LeftIdx}}{{$line.LeftIdx}}{{end}}"><span rel="{{if $line.LeftIdx}}diff-{{$.FileNameHash}}L{{$line.LeftIdx}}{{end}}"></span></td>
-			<td class="blob-excerpt lines-escape lines-escape-old">{{if and $line.LeftIdx $inlineDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.locale}}"></a>{{end}}</td>
+			<td class="blob-excerpt lines-escape lines-escape-old">{{if and $line.LeftIdx $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.locale}}"></button>{{end}}</td>
 			<td class="blob-excerpt lines-type-marker lines-type-marker-old">{{if $line.LeftIdx}}<span class="gt-mono" data-type-marker=""></span>{{end}}</td>
 			<td class="blob-excerpt lines-code lines-code-old">{{/*
 				*/}}{{if $line.LeftIdx}}{{template "repo/diff/section_code" dict "diff" $inlineDiff "locale" $.locale}}{{else}}{{/*
@@ -32,7 +34,7 @@
 				*/}}{{end}}{{/*
 			*/}}</td>
 			<td class="lines-num lines-num-new" data-line-num="{{if $line.RightIdx}}{{$line.RightIdx}}{{end}}"><span rel="{{if $line.RightIdx}}diff-{{$.FileNameHash}}R{{$line.RightIdx}}{{end}}"></span></td>
-			<td class="blob-excerpt lines-escape lines-escape-new">{{if and $line.RightIdx $inlineDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.locale}}"></a>{{end}}</td>
+			<td class="blob-excerpt lines-escape lines-escape-new">{{if and $line.RightIdx $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.locale}}"></button>{{end}}</td>
 			<td class="blob-excerpt lines-type-marker lines-type-marker-new">{{if $line.RightIdx}}<span class="gt-mono" data-type-marker=""></span>{{end}}</td>
 			<td class="blob-excerpt lines-code lines-code-new">{{/*
 				*/}}{{if $line.RightIdx}}{{template "repo/diff/section_code" dict "diff" $inlineDiff "locale" $.locale}}{{else}}{{/*
@@ -47,28 +49,30 @@
 	<tr class="{{.GetHTMLDiffLineType}}-code nl-{{$k}} ol-{{$k}}">
 		{{if eq .GetType 4}}
 			<td colspan="2" class="lines-num">
-				{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 5)}}
-					<a role="button" class="blob-excerpt" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=down&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
-						{{svg "octicon-fold-down"}}
-					</a>
-				{{end}}
-				{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 4)}}
-					<a role="button" class="blob-excerpt" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=up&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
-						{{svg "octicon-fold-up"}}
-					</a>
-				{{end}}
-				{{if eq $line.GetExpandDirection 2}}
-					<a role="button" class="blob-excerpt" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
-						{{svg "octicon-fold"}}
-					</a>
-				{{end}}
+				<div class="gt-df">
+					{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 5)}}
+						<button class="code-expander-button" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=down&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
+							{{svg "octicon-fold-down"}}
+						</button>
+					{{end}}
+					{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 4)}}
+						<button class="code-expander-button" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=up&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
+							{{svg "octicon-fold-up"}}
+						</button>
+					{{end}}
+					{{if eq $line.GetExpandDirection 2}}
+						<button class="code-expander-button" data-url="{{$.RepoLink}}/blob_excerpt/{{PathEscape $.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=&wiki={{$.PageIsWiki}}" data-anchor="{{$.Anchor}}">
+							{{svg "octicon-fold"}}
+						</button>
+					{{end}}
+				</div>
 			</td>
 		{{else}}
 			<td class="lines-num lines-num-old" data-line-num="{{if $line.LeftIdx}}{{$line.LeftIdx}}{{end}}"><span rel="{{if $line.LeftIdx}}diff-{{$.FileNameHash}}L{{$line.LeftIdx}}{{end}}"></span></td>
 			<td class="lines-num lines-num-new" data-line-num="{{if $line.RightIdx}}{{$line.RightIdx}}{{end}}"><span rel="{{if $line.RightIdx}}diff-{{$.FileNameHash}}R{{$line.RightIdx}}{{end}}"></span></td>
 		{{end}}
 		{{$inlineDiff := $.section.GetComputedInlineDiffFor $line $.locale}}
-		<td class="blob-excerpt lines-escape">{{if $inlineDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.locale}}"></a>{{end}}</td>
+		<td class="blob-excerpt lines-escape">{{if $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.locale}}"></button>{{end}}</td>
 		<td class="blob-excerpt lines-type-marker"><span class="gt-mono" data-type-marker="{{$line.GetLineTypeMarker}}"></span></td>
 		<td class="blob-excerpt lines-code{{if (not $line.RightIdx)}} lines-code-old{{end}}"><code {{if $inlineDiff.EscapeStatus.Escaped}}class="code-inner has-escaped" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.locale}}"{{else}}class="code-inner"{{end}}>{{$inlineDiff.Content}}</code></td>
 	</tr>
diff --git a/templates/repo/diff/box.tmpl b/templates/repo/diff/box.tmpl
index 26b863acea..740b39dbd5 100644
--- a/templates/repo/diff/box.tmpl
+++ b/templates/repo/diff/box.tmpl
@@ -90,13 +90,13 @@
 						<div class="diff-file-box diff-box file-content {{TabSizeClass $.Editorconfig $file.Name}} gt-mt-3" id="diff-{{$file.NameHash}}" data-old-filename="{{$file.OldName}}" data-new-filename="{{$file.Name}}" {{if or ($file.ShouldBeHidden) (not $isExpandable)}}data-folded="true"{{end}}>
 							<h4 class="diff-file-header sticky-2nd-row ui top attached normal header gt-df gt-ac gt-sb">
 								<div class="diff-file-name gt-df gt-ac gt-mr-3">
-									<a role="button" class="fold-file muted gt-mr-2" {{if not $isExpandable}}style="visibility: hidden"{{end}}>
+									<button class="fold-file ui button button-ghost gt-p-0 gt-mr-3{{if not $isExpandable}} gt-invisible{{end}}">
 										{{if $file.ShouldBeHidden}}
 											{{svg "octicon-chevron-right" 18}}
 										{{else}}
 											{{svg "octicon-chevron-down" 18}}
 										{{end}}
-									</a>
+									</button>
 									<div class="gt-bold gt-df gt-ac gt-mono">
 										{{if $file.IsBin}}
 											<span class="gt-ml-1 gt-mr-3">
@@ -125,8 +125,8 @@
 										<span class="ui basic label">{{$.locale.Tr "repo.diff.protected"}}</span>
 									{{end}}
 									{{if not (or $file.IsIncomplete $file.IsBin $file.IsSubmodule)}}
-										<a class="ui basic tiny button unescape-button">{{$.locale.Tr "repo.unescape_control_characters"}}</a>
-										<a class="ui basic tiny button escape-button gt-hidden">{{$.locale.Tr "repo.escape_control_characters"}}</a>
+										<button class="ui basic tiny button unescape-button">{{$.locale.Tr "repo.unescape_control_characters"}}</button>
+										<button class="ui basic tiny button escape-button gt-hidden">{{$.locale.Tr "repo.escape_control_characters"}}</button>
 									{{end}}
 									{{if and (not $file.IsSubmodule) (not $.PageIsWiki)}}
 										{{if $file.IsDeleted}}
diff --git a/templates/repo/diff/section_split.tmpl b/templates/repo/diff/section_split.tmpl
index 42aed85084..cb96d64056 100644
--- a/templates/repo/diff/section_split.tmpl
+++ b/templates/repo/diff/section_split.tmpl
@@ -16,23 +16,25 @@
 			<tr class="{{.GetHTMLDiffLineType}}-code nl-{{$k}} ol-{{$k}}" data-line-type="{{.GetHTMLDiffLineType}}">
 				{{if eq .GetType 4}}
 					<td class="lines-num lines-num-old">
+						<div class="gt-df">
 						{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 5)}}
-							<a role="button" class="blob-excerpt" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=down&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+							<button class="code-expander-button" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=down&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 								{{svg "octicon-fold-down"}}
-							</a>
+							</button>
 						{{end}}
 						{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 4)}}
-							<a role="button" class="blob-excerpt" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=up&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+							<button class="code-expander-button" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=up&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 								{{svg "octicon-fold-up"}}
-							</a>
+							</button>
 						{{end}}
 						{{if eq $line.GetExpandDirection 2}}
-							<a role="button" class="blob-excerpt" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+							<button class="code-expander-button" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=split&direction=&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 								{{svg "octicon-fold"}}
-							</a>
+							</button>
 						{{end}}
+						</div>
 					</td>{{$inlineDiff := $section.GetComputedInlineDiffFor $line $.root.locale}}
-					<td class="lines-escape lines-escape-old">{{if $inlineDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.root.locale}}"></a>{{end}}</td>
+					<td class="lines-escape lines-escape-old">{{if $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.root.locale}}"></button>{{end}}</td>
 					<td colspan="6" class="lines-code lines-code-old ">{{/*
 						*/}}{{template "repo/diff/section_code" dict "diff" $inlineDiff "locale" $.root.locale}}{{/*
 					*/}}</td>
@@ -41,7 +43,7 @@
 					{{- $leftDiff := ""}}{{if $line.LeftIdx}}{{$leftDiff = $section.GetComputedInlineDiffFor $line $.root.locale}}{{end}}
 					{{- $rightDiff := ""}}{{if $match.RightIdx}}{{$rightDiff = $section.GetComputedInlineDiffFor $match $.root.locale}}{{end}}
 					<td class="lines-num lines-num-old del-code" data-line-num="{{$line.LeftIdx}}"><span rel="diff-{{$file.NameHash}}L{{$line.LeftIdx}}"></span></td>
-					<td class="lines-escape del-code lines-escape-old">{{if $line.LeftIdx}}{{if $leftDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $leftDiff "locale" $.root.locale}}"></a>{{end}}{{end}}</td>
+					<td class="lines-escape del-code lines-escape-old">{{if $line.LeftIdx}}{{if $leftDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $leftDiff "locale" $.root.locale}}"></a>{{end}}{{end}}</td>
 					<td class="lines-type-marker lines-type-marker-old del-code"><span class="gt-mono" data-type-marker="{{$line.GetLineTypeMarker}}"></span></td>
 					<td class="lines-code lines-code-old del-code">{{/*
 						*/}}{{if and $.root.SignedUserID $.root.PageIsPullFiles}}{{/*
@@ -56,7 +58,7 @@
 						*/}}{{end}}{{/*
 					*/}}</td>
 					<td class="lines-num lines-num-new add-code" data-line-num="{{if $match.RightIdx}}{{$match.RightIdx}}{{end}}"><span rel="{{if $match.RightIdx}}diff-{{$file.NameHash}}R{{$match.RightIdx}}{{end}}"></span></td>
-					<td class="lines-escape add-code lines-escape-new">{{if $match.RightIdx}}{{if $rightDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $rightDiff "locale" $.root.locale}}"></a>{{end}}{{end}}</td>
+					<td class="lines-escape add-code lines-escape-new">{{if $match.RightIdx}}{{if $rightDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $rightDiff "locale" $.root.locale}}"></button>{{end}}{{end}}</td>
 					<td class="lines-type-marker lines-type-marker-new add-code">{{if $match.RightIdx}}<span class="gt-mono" data-type-marker="{{$match.GetLineTypeMarker}}"></span>{{end}}</td>
 					<td class="lines-code lines-code-new add-code">{{/*
 						*/}}{{if and $.root.SignedUserID $.root.PageIsPullFiles}}{{/*
@@ -73,7 +75,7 @@
 				{{else}}
 					{{$inlineDiff := $section.GetComputedInlineDiffFor $line $.root.locale}}
 					<td class="lines-num lines-num-old" data-line-num="{{if $line.LeftIdx}}{{$line.LeftIdx}}{{end}}"><span rel="{{if $line.LeftIdx}}diff-{{$file.NameHash}}L{{$line.LeftIdx}}{{end}}"></span></td>
-					<td class="lines-escape lines-escape-old">{{if $line.LeftIdx}}{{if $inlineDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.root.locale}}"></a>{{end}}{{end}}</td>
+					<td class="lines-escape lines-escape-old">{{if $line.LeftIdx}}{{if $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.root.locale}}"></button>{{end}}{{end}}</td>
 					<td class="lines-type-marker lines-type-marker-old">{{if $line.LeftIdx}}<span class="gt-mono" data-type-marker="{{$line.GetLineTypeMarker}}"></span>{{end}}</td>
 					<td class="lines-code lines-code-old">{{/*
 						*/}}{{if and $.root.SignedUserID $.root.PageIsPullFiles (not (eq .GetType 2))}}{{/*
@@ -88,7 +90,7 @@
 						*/}}{{end}}{{/*
 					*/}}</td>
 					<td class="lines-num lines-num-new" data-line-num="{{if $line.RightIdx}}{{$line.RightIdx}}{{end}}"><span rel="{{if $line.RightIdx}}diff-{{$file.NameHash}}R{{$line.RightIdx}}{{end}}"></span></td>
-					<td class="lines-escape lines-escape-new">{{if $line.RightIdx}}{{if $inlineDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.root.locale}}"></a>{{end}}{{end}}</td>
+					<td class="lines-escape lines-escape-new">{{if $line.RightIdx}}{{if $inlineDiff.EscapeStatus.Escaped}}<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.root.locale}}"></button>{{end}}{{end}}</td>
 					<td class="lines-type-marker lines-type-marker-new">{{if $line.RightIdx}}<span class="gt-mono" data-type-marker="{{$line.GetLineTypeMarker}}"></span>{{end}}</td>
 					<td class="lines-code lines-code-new">{{/*
 						*/}}{{if and $.root.SignedUserID $.root.PageIsPullFiles (not (eq .GetType 3))}}{{/*
diff --git a/templates/repo/diff/section_unified.tmpl b/templates/repo/diff/section_unified.tmpl
index 8bf331f6db..d970853159 100644
--- a/templates/repo/diff/section_unified.tmpl
+++ b/templates/repo/diff/section_unified.tmpl
@@ -12,21 +12,23 @@
 			{{if eq .GetType 4}}
 				{{if $.root.AfterCommitID}}
 					<td colspan="2" class="lines-num">
-						{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 5)}}
-							<a role="button" class="blob-excerpt" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=down&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
-								{{svg "octicon-fold-down"}}
-							</a>
-						{{end}}
-						{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 4)}}
-							<a role="button" class="blob-excerpt" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=up&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
-								{{svg "octicon-fold-up"}}
-							</a>
-						{{end}}
-						{{if eq $line.GetExpandDirection 2}}
-							<a role="button" class="blob-excerpt" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
-								{{svg "octicon-fold"}}
-							</a>
-						{{end}}
+						<div class="gt-df">
+							{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 5)}}
+								<button class="code-expander-button" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=down&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+									{{svg "octicon-fold-down"}}
+								</button>
+							{{end}}
+							{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 4)}}
+								<button class="code-expander-button" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=up&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+									{{svg "octicon-fold-up"}}
+								</button>
+							{{end}}
+							{{if eq $line.GetExpandDirection 2}}
+								<button class="code-expander-button" data-url="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}" data-query="{{$line.GetBlobExcerptQuery}}&style=unified&direction=&wiki={{$.root.PageIsWiki}}" data-anchor="diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+									{{svg "octicon-fold"}}
+								</button>
+							{{end}}
+						</div>
 					</td>
 				{{else}}
 					{{/* for code file preview page or comment diffs on pull comment pages, do not show the expansion arrows */}}
@@ -37,7 +39,11 @@
 				<td class="lines-num lines-num-new" data-line-num="{{if $line.RightIdx}}{{$line.RightIdx}}{{end}}"><span rel="{{if $line.RightIdx}}diff-{{$file.NameHash}}R{{$line.RightIdx}}{{end}}"></span></td>
 			{{end}}
 			{{$inlineDiff := $section.GetComputedInlineDiffFor $line $.root.locale -}}
-			<td class="lines-escape">{{if $inlineDiff.EscapeStatus.Escaped}}<a href="" class="toggle-escape-button" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.root.locale}}"></a>{{end}}</td>
+			<td class="lines-escape">
+				{{- if $inlineDiff.EscapeStatus.Escaped -}}
+					<button class="toggle-escape-button button button-ghost" title="{{template "repo/diff/escape_title" dict "diff" $inlineDiff "locale" $.root.locale}}"></button>
+				{{- end -}}
+			</td>
 			<td class="lines-type-marker"><span class="gt-mono" data-type-marker="{{$line.GetLineTypeMarker}}"></span></td>
 			{{if eq .GetType 4}}
 				<td class="chroma lines-code blob-hunk">{{/*
diff --git a/templates/repo/issue/labels/labels_selector_field.tmpl b/templates/repo/issue/labels/labels_selector_field.tmpl
index 00d852bba9..350cf631e8 100644
--- a/templates/repo/issue/labels/labels_selector_field.tmpl
+++ b/templates/repo/issue/labels/labels_selector_field.tmpl
@@ -1,10 +1,10 @@
 <div class="ui {{if or (not .HasIssuesOrPullsWritePermission) .Repository.IsArchived}}disabled{{end}} floating jump select-label dropdown">
-	<a class="text gt-df gt-ac muted">
+	<span class="text gt-df gt-ac muted">
 		<strong>{{.locale.Tr "repo.issues.new.labels"}}</strong>
 		{{if and .HasIssuesOrPullsWritePermission (not .Repository.IsArchived)}}
 			{{svg "octicon-gear" 16 "gt-ml-2"}}
 		{{end}}
-	</a>
+	</span>
 	<div class="filter menu" {{if .Issue}}data-action="update" data-issue-id="{{$.Issue.ID}}" data-update-url="{{$.RepoLink}}/issues/labels"{{else}}data-id="#label_ids"{{end}}>
 		<div class="header" style="text-transform: none;font-size:16px;">{{.locale.Tr "repo.issues.new.add_labels_title"}}</div>
 		{{if or .Labels .OrgLabels}}
diff --git a/templates/repo/issue/view_title.tmpl b/templates/repo/issue/view_title.tmpl
index f9febbde01..0857025495 100644
--- a/templates/repo/issue/view_title.tmpl
+++ b/templates/repo/issue/view_title.tmpl
@@ -45,12 +45,12 @@
 			{{if .Issue.IsPull}}
 				{{$headHref := .HeadTarget|Escape}}
 				{{if .HeadBranchLink}}
-					{{$headHref = printf "<a href=\"%s\">%s</a>" (.HeadBranchLink | Escape) $headHref}}
+					{{$headHref = printf `<a href="%s">%s</a>` (.HeadBranchLink | Escape) $headHref}}
 				{{end}}
-				{{$headHref = printf "%s <a data-tooltip-content=\"%s\" data-clipboard-text=\"%s\">%s</a>" $headHref (.locale.Tr "copy_branch") (.HeadTarget | Escape) (svg "octicon-copy" 14)}}
+				{{$headHref = printf `%s <button class="button button-ghost" data-tooltip-content="%s" data-clipboard-text="%s">%s</button>` $headHref (.locale.Tr "copy_branch") (.HeadTarget | Escape) (svg "octicon-copy" 14)}}
 				{{$baseHref := .BaseTarget|Escape}}
 				{{if .BaseBranchLink}}
-					{{$baseHref = printf "<a href=\"%s\">%s</a>" (.BaseBranchLink | Escape) $baseHref}}
+					{{$baseHref = printf `<a href="%s">%s</a>` (.BaseBranchLink | Escape) $baseHref}}
 				{{end}}
 				{{if .Issue.PullRequest.HasMerged}}
 					{{$mergedStr:= TimeSinceUnix .Issue.PullRequest.MergedUnix $.locale}}
diff --git a/templates/repo/view_file.tmpl b/templates/repo/view_file.tmpl
index 03f90d71f2..f50d8646de 100644
--- a/templates/repo/view_file.tmpl
+++ b/templates/repo/view_file.tmpl
@@ -36,8 +36,8 @@
 					{{end}}
 					<a class="ui mini basic button" href="{{.RepoLink}}/commits/{{.BranchNameSubURL}}/{{PathEscapeSegments .TreePath}}">{{.locale.Tr "repo.file_history"}}</a>
 					{{if .EscapeStatus.Escaped}}
-						<a class="ui mini basic button unescape-button gt-hidden">{{.locale.Tr "repo.unescape_control_characters"}}</a>
-						<a class="ui mini basic button escape-button">{{.locale.Tr "repo.escape_control_characters"}}</a>
+						<button class="ui mini basic button unescape-button gt-hidden">{{.locale.Tr "repo.unescape_control_characters"}}</button>
+						<button class="ui mini basic button escape-button">{{.locale.Tr "repo.escape_control_characters"}}</button>
 					{{end}}
 				</div>
 				<a download href="{{$.RawFileLink}}"><span class="btn-octicon" data-tooltip-content="{{.locale.Tr "repo.download_file"}}">{{svg "octicon-download"}}</span></a>
@@ -58,8 +58,8 @@
 					{{end}}
 				{{end}}
 			{{else if .EscapeStatus.Escaped}}
-				<a class="ui mini basic button unescape-button gt-mr-2 gt-hidden">{{.locale.Tr "repo.unescape_control_characters"}}</a>
-				<a class="ui mini basic button escape-button gt-mr-2">{{.locale.Tr "repo.escape_control_characters"}}</a>
+				<button class="ui mini basic button unescape-button gt-mr-2 gt-hidden">{{.locale.Tr "repo.unescape_control_characters"}}</button>
+				<button class="ui mini basic button escape-button gt-mr-2">{{.locale.Tr "repo.escape_control_characters"}}</button>
 			{{end}}
 		</div>
 	</h4>
@@ -107,7 +107,7 @@
 						<tr>
 							<td id="L{{$line}}" class="lines-num"><span id="L{{$line}}" data-line-number="{{$line}}"></span></td>
 							{{if $.EscapeStatus.Escaped}}
-								<td class="lines-escape">{{if (index $.LineEscapeStatus $idx).Escaped}}<a href="" class="toggle-escape-button" title="{{if (index $.LineEscapeStatus $idx).HasInvisible}}{{$.locale.Tr "repo.invisible_runes_line"}} {{end}}{{if (index $.LineEscapeStatus $idx).HasAmbiguous}}{{$.locale.Tr "repo.ambiguous_runes_line"}}{{end}}"></a>{{end}}</td>
+								<td class="lines-escape">{{if (index $.LineEscapeStatus $idx).Escaped}}<button class="toggle-escape-button button button-ghost" title="{{if (index $.LineEscapeStatus $idx).HasInvisible}}{{$.locale.Tr "repo.invisible_runes_line"}} {{end}}{{if (index $.LineEscapeStatus $idx).HasAmbiguous}}{{$.locale.Tr "repo.ambiguous_runes_line"}}{{end}}"></button>{{end}}</td>
 							{{end}}
 							<td rel="L{{$line}}" class="lines-code chroma"><code class="code-inner">{{$code | Safe}}</code></td>
 						</tr>