init feat Prev Next post links on single post page (adityatelange#180)

usage =>
in site config add 
Params:
   ShowPostNavLinks: true

assets/css/post-single.css

@@ -294,7 +294,8 @@
 }
 
 .post-tags a,
-.share-buttons {
+.share-buttons,
+.paginav {
     border-radius: var(--radius);
     background: var(--code-bg);
     border: 1px solid var(--border)
@@ -310,7 +311,8 @@
     background: var(--code-bg)
 }
 
-.post-tags a:hover {
+.post-tags a:hover,
+.paginav a:hover {
     background: var(--border)
 }
 
@@ -374,3 +376,41 @@ h6:hover .anchor {
 .post-content table::-webkit-scrollbar-thumb {
     border-width: 2px;
 }
+
+.paginav {
+    margin: 10px 0;
+    display: flex;
+    line-height: 30px;
+    border-radius: var(--radius);
+}
+
+.paginav a {
+    padding-inline-start: 14px;
+    padding-inline-end: 14px;
+    border-radius: var(--radius);
+}
+
+.paginav .title {
+    letter-spacing: 1px;
+    text-transform: uppercase;
+    font-size: small;
+    color: var(--secondary);
+}
+
+.paginav .prev,
+.paginav .next {
+    width: 50%;
+}
+
+.paginav span:hover:not(.title) {
+    box-shadow: 0 1px 0;
+}
+
+.paginav .next {
+    margin-inline-start: auto;
+    text-align: right;
+}
+
+[dir="rtl"] .paginav .next {
+    text-align: left;
+}

layouts/_default/single.html

@@ -57,6 +57,27 @@ <h1 class="post-title">
       {{- end }}
     </ul>
     {{- end }}
+    {{- if .Site.Params.ShowPostNavLinks }}
+    {{- $pages := where site.RegularPages "Type" "in" site.Params.mainSections }}
+    {{- if and (gt (len $pages) 1) (in $pages . ) }}
+    <nav class="paginav">
+      {{- with $pages.Next . }}
+      <a class="prev" href="{{.Permalink}}">
+        <span class="title">« {{ i18n "prev_page" }}</span>
+        <br>
+        <span>{{- .Name -}}</span>
+      </a>
+      {{- end}}
+      {{- with $pages.Prev . }}
+      <a class="next" href="{{.Permalink}}">
+        <span class="title">{{ i18n "next_page" }} »</span>
+        <br>
+        <span>{{- .Name -}}</span>
+      </a>
+      {{- end}}
+    </nav>
+    {{- end }}
+    {{- end }}
     {{- if (and .Site.Params.ShowShareButtons (ne .Params.disableShare true) ) }}
     {{- partial "share_icons.html" . }}
     {{- end }}