Colophon: add newsletter subscription block linking to Buttondown

Author: modusensus

src/pages/colophon.astro

@@ -102,7 +102,16 @@ import BaseLayout from '../layouts/BaseLayout.astro';
         </a>
       </div>
 
-      <div class="mono-label group-label">07 — CONTACT</div>
+      <div class="mono-label group-label">07 — NEWSLETTER</div>
+      <div class="newsletter-block">
+        <p class="nl-lead">新文章摘要与精选内容，直接送进邮箱。低频率、尊重注意力，随时可退。</p>
+        <a class="nl-cta" href="https://buttondown.com/modusensus" target="_blank" rel="noopener noreferrer">
+          <span>订阅专栏信</span>
+          <span class="nl-arrow" aria-hidden="true">→</span>
+        </a>
+      </div>
+
+      <div class="mono-label group-label">08 — CONTACT</div>
       <div class="about-block">
         <div class="contact-row">
           <a href="https://github.com/modusensus" class="footer-icon" target="_blank" rel="noopener">
@@ -128,14 +137,14 @@ import BaseLayout from '../layouts/BaseLayout.astro';
         </div>
       </div>
 
-      <div class="mono-label group-label">08 — RESEARCH</div>
+      <div class="mono-label group-label">09 — RESEARCH</div>
       <div class="about-block pills-row">
         <span class="pill">空间公平与城市可达性</span>
         <span class="pill">数字治理与 AI 政策</span>
         <span class="pill">人机协作与自动化工作流</span>
       </div>
 
-      <div class="mono-label group-label">09 — PRIVACY &amp; SECURITY</div>
+      <div class="mono-label group-label">10 — PRIVACY &amp; SECURITY</div>
       <div class="about-block legal-block">
         <div class="legal-row" id="privacy">
           <span class="mono-meta">PRIVACY · 隐私声明</span>
@@ -242,4 +251,37 @@ import BaseLayout from '../layouts/BaseLayout.astro';
   .stack-row { grid-template-columns: 1fr; gap: 8px; }
   .legal-row { grid-template-columns: 1fr; gap: 6px; }
 }
+
+/* ── NEWSLETTER 订阅块：报纸风，油墨双线框 + mono 标签 + 大号 CTA ── */
+.newsletter-block {
+  padding: 22px 24px;
+  margin: 6px 0 8px;
+  background: var(--paper-raise);
+  border: 1px solid var(--ink);
+  box-shadow: 3px 5px 0 rgba(34, 30, 24, 0.08);
+}
+.nl-lead {
+  font-family: var(--font-cn);
+  font-size: 14px; line-height: 1.8;
+  color: var(--ink-soft);
+  margin: 0 0 18px;
+}
+.nl-cta {
+  display: inline-flex;
+  align-items: center;
+  gap: 12px;
+  text-decoration: none;
+  background: var(--ink); color: var(--paper);
+  padding: 11px 20px;
+  font-family: var(--font-mono);
+  font-size: 12px; font-weight: 700;
+  letter-spacing: 0.1em;
+  text-transform: uppercase;
+  transition: background 0.2s var(--ease-out), gap 0.2s var(--ease-out);
+}
+.nl-cta:hover {
+  background: var(--c-pink);
+  gap: 16px;
+}
+.nl-arrow { font-size: 15px; line-height: 1; }
 </style>