Redesign homepage layout and update content

Align homepage content to center, adjust sidebar width and page
max-width, update hero text to Chinese, and apply dark background
for the site.

layouts/hextra-home.html

@@ -1,11 +1,14 @@
 {{ define "main" }}
 <div class="hx:mx-auto hx:flex hextra-max-page-width">
-    {{ partial "sidebar.html" (dict "context" . "disableSidebar" true) }}
+    {{ partial "sidebar.html" (dict "context" . "disableSidebar" true
+    "displayPlaceholder" true) }}
     <main
         id="content"
-        class="hx:w-full hx:break-words hx:min-h-[calc(100vh-var(--navbar-height))] hx:min-w-0 hx:pb-8 hx:pt-8 hx:md:pt-12 hx:pl-[max(env(safe-area-inset-left),1.5rem)] hx:pr-[max(env(safe-area-inset-left),1.5rem)]"
+        class="hx:w-full hx:break-words hx:min-h-[calc(100vh-var(--navbar-height))] hx:min-w-0 hx:pb-8 hx:px-6 hx:pt-4 hx:md:px-12"
     >
-        <div class="hx:flex hx:flex-col hx:items-start">{{ .Content }}</div>
+        <div class="hx:flex hx:flex-col hx:items-center hx:text-center">
+            {{ .Content }}
+        </div>
 
         {{- $pages := where .Site.RegularPages "Section" "blog" }} {{- $pages =
         $pages.ByDate.Reverse }} {{- $recent := first 6 $pages }} {{- $readMore
@@ -46,5 +49,6 @@
             {{- end }}
         </div>
     </main>
+    <div class="hx:max-xl:hidden hx:h-0 hx:w-64 hx:shrink-0"></div>
 </div>
 {{ end }}