主题功能同步：vivid 页脚补社交按钮排（含源码入口，居中）；classic 文章页补右栏目录（滚动高亮）与顶部阅读进度条——快发盒经核实两套 UI 均已存在，无需补

frontend/src/ui/yohaku/YohakuFoot.vue

@@ -1,6 +1,12 @@
 <script setup>
 import { RouterLink } from 'vue-router'
 import { site } from '../../site'
+import { socialIcon } from '../../socialIcons'
+
+// 社交按钮与 classic 页脚同源：后台「社交链接」+ 固定源码仓库入口
+const PROJECT_REPO = 'https://git.gopher.ink/mirrors2/ONE'
+const social = (site.social_links || []).concat([{ label: '源码', url: PROJECT_REPO }])
+  .filter((s) => s && s.url)
 
 // 余白页脚。对应设计稿的 <footer class="foot">。
 //
@@ -21,6 +27,20 @@ const links = [
 <template>
   <footer class="foot">
     <div class="quote">What&rsquo;s left unsaid holds the most weight.</div>
+    <div v-if="social.length" class="foot-social">
+      <a
+        v-for="s in social"
+        :key="s.label + s.url"
+        :href="s.url"
+        :title="s.label"
+        :aria-label="s.label"
+        :target="s.url.startsWith('http') ? '_blank' : undefined"
+        :rel="s.url.startsWith('http') ? 'noopener' : undefined"
+      >
+        <svg v-if="socialIcon(s.url)" viewBox="0 0 24 24" aria-hidden="true"><path :d="socialIcon(s.url)" /></svg>
+        <span v-else>{{ s.label }}</span>
+      </a>
+    </div>
     <div>{{ site.footer_note }}<template v-if="site.icp"> · {{ site.icp }}</template></div>
     <div class="foot-nav">
       <template v-for="(l, i) in links" :key="l.to">

frontend/src/ui/yohaku/chrome.css

@@ -169,6 +169,15 @@ html[data-ui='vivid'] .foot {max-width:1100px;margin:40px auto 0;padding:28px 28
   border-top:1px solid var(--line);
   text-align:center;color:var(--muted);font-size:12.5px;line-height:2;}
 html[data-ui='vivid'] .foot a {color:var(--accent);font-weight:600;transition:opacity .25s}
+/* 页脚社交排：图标居中一行，与 classic 页脚同步 */
+html[data-ui='vivid'] .foot-social {display:flex;justify-content:center;align-items:center;
+  gap:18px;margin:14px 0 18px;}
+html[data-ui='vivid'] .foot-social a {color:var(--soft);font-weight:400;
+  display:inline-flex;align-items:center;justify-content:center;
+  width:30px;height:30px;border-radius:8px;transition:color .25s,background .25s;}
+html[data-ui='vivid'] .foot-social a:hover {color:var(--accent);background:var(--accent-soft);}
+html[data-ui='vivid'] .foot-social svg {width:17px;height:17px;fill:currentColor;}
+html[data-ui='vivid'] .foot-social span {font-size:12px;}
 @media (hover: hover) and (pointer: fine) {
   html[data-ui='vivid'] .foot a:hover {opacity:.75}
 }