Fix Hugo v0.156+ deprecations: Site.Author, Site.Data, and libsass

- Replace .Site.Author.{email,name} with .Site.Params.{social.email,author} in rss.xml
- Replace .Site.Data with hugo.Data in footer, social, and contact-box templates
- Switch SCSS transpiler from libsass to dartsass; add @use "sass:color" and replace darken()/lighten() with color.adjust()

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

themes/hugo-theme-ipng/assets/styles.scss

@@ -1,3 +1,4 @@
+@use "sass:color";
 // Colors
 $midnight-blue: #07608f;
 $midnight-matte: #4c7e99;
@@ -763,7 +764,7 @@ table {
   border: 2px solid $ipng-orange;
   tr {
     &:nth-child(even) {
-      background-color: darken($table-cell-background, 10%);
+      background-color: color.adjust($table-cell-background, $lightness: -10%);
     }
   }
   th, td {
@@ -771,7 +772,7 @@ table {
   }
   th {
     color: $ipng-orange;
-    background-color: lighten($table-header-background, 3%);
+    background-color: color.adjust($table-header-background, $lightness: 3%);
     border-bottom: 3px solid $ipng-orange;
     font-weight: bold;
   }

themes/hugo-theme-ipng/layouts/_default/rss.xml

@@ -9,14 +9,14 @@
         <language>{{.}}</language>
         {{end}}
 
-        {{ with .Site.Author.email }}
+        {{ with .Site.Params.social.email }}
         <managingEditor>{{.}}
-            {{ with $.Site.Author.name }} ({{.}}){{end}}
+            {{ with $.Site.Params.author }} ({{.}}){{end}}
         </managingEditor>
         {{end}}
 
-        {{ with .Site.Author.email }}
+        {{ with .Site.Params.social.email }}
-        <webMaster>{{.}}{{ with $.Site.Author.name }} ({{.}}){{end}}
+        <webMaster>{{.}}{{ with $.Site.Params.author }} ({{.}}){{end}}
         </webMaster>
         {{end}}
 
@@ -38,7 +38,7 @@
           <title>{{ .Title }}</title>
           <link>{{ .Permalink }}</link>
           <pubDate>{{ .Date.Format "Mon, 02 Jan 2006 15:04:05 -0700" | safeHTML }}</pubDate>
-          {{ with .Site.Author.email }}<author>{{.}}{{ with $.Site.Author.name }} ({{.}}){{end}}</author>{{end}}
+          {{ with .Site.Params.social.email }}<author>{{.}}{{ with $.Site.Params.author }} ({{.}}){{end}}</author>{{end}}
           <guid>{{ .Permalink }}</guid>
           <description>{{ .Summary | markdownify }}</description>
         </item>

themes/hugo-theme-ipng/layouts/partials/footer.html

@@ -1,6 +1,6 @@
 
 <footer class='page-footer'>
-{{- $socialMap := .Site.Data.notrack.social }}
+{{- $socialMap := hugo.Data.notrack.social }}
 {{- with $.Site.Params.social }}
     <div class="social">
         <ul>

themes/hugo-theme-ipng/layouts/partials/head.html

@@ -3,7 +3,7 @@
     <title>{{ .Site.Title }} {{ with .Title }}- {{ . }} {{ end }}</title>
     <link rel="stylesheet" type="text/css" href="{{ "css/fonts.css" | relURL }}">
     <link rel="stylesheet" type="text/css" href="{{ "css/fontawesome.css" | relURL }}">
-    {{ $options := dict "transpiler" "libsass" "targetPath" "css/styles.css" -}}
+    {{ $options := dict "transpiler" "dartsass" "targetPath" "css/styles.css" -}}
     {{ $style := resources.Get "styles.scss" | toCSS $options | minify | fingerprint -}}
     <link rel="stylesheet" type="text/css" href="{{ $style.RelPermalink }}">
     {{ with resources.Get "css/userstyles.css" }}

themes/hugo-theme-ipng/layouts/shortcodes/contact-box.html

@@ -1,5 +1,5 @@
 {{ with $.Page.Site.Params.social }}
-{{ $socialMap := $.Page.Site.Data.notrack.social }}
+{{ $socialMap := hugo.Data.notrack.social }}
 {{ $width := default "12em" (.Params.Get "width") }}
 {{ $height := default "auto" (.Params.Get "height") }}
 {{ $float := default "right" (.Params.Get "float") }}

themes/hugo-theme-ipng/layouts/shortcodes/social.html

@@ -1,4 +1,4 @@
-{{ $socialMap := .Site.Data.notrack.social }}
+{{ $socialMap := hugo.Data.notrack.social }}
 
 {{ with $.Site.Params.social }}
     <div class="social">