chore: remove Bund Summit 2026 banner from homepage

Author: TreeLin

_layouts/home.html

@@ -128,16 +128,6 @@
 .btn-secondary { background: var(--canvas); color: var(--ink); border: 1px solid var(--hairline); }
 .btn-secondary:hover { border-color: var(--ink); }
 
-/* Bund Summit 2026 banner */
-.bund-banner { display: block; text-decoration: none; padding: 0 24px; max-width: 1100px; margin: 40px auto 0; }
-.bund-banner-inner { position: relative; overflow: hidden; border-radius: var(--rounded-lg); padding: 26px 32px; background: linear-gradient(120deg, #5319E7 0%, #7928ca 55%, #007cf0 100%); color: #fff; display: flex; align-items: center; justify-content: space-between; gap: 24px; transition: transform 0.2s, box-shadow 0.2s; }
-.bund-banner:hover .bund-banner-inner { transform: translateY(-2px); box-shadow: 0 12px 32px rgba(83,25,231,0.28); }
-.bund-tag { display: inline-block; font-size: 12px; font-weight: 600; letter-spacing: 0.5px; padding: 4px 12px; border-radius: 100px; background: rgba(255,255,255,0.18); margin-bottom: 12px; }
-.bund-banner-text h2 { font-size: 22px; font-weight: 600; letter-spacing: -0.5px; margin-bottom: 8px; color: #fff; }
-.bund-banner-text p { font-size: 14px; line-height: 1.6; color: rgba(255,255,255,0.9); max-width: 640px; }
-.bund-banner-cta { flex-shrink: 0; font-size: 14px; font-weight: 600; padding: 12px 22px; border-radius: 100px; background: #fff; color: #5319E7; white-space: nowrap; }
-@media (max-width: 768px) { .bund-banner-inner { flex-direction: column; align-items: flex-start; } .bund-banner-text h2 { font-size: 19px; } .bund-banner-cta { align-self: stretch; text-align: center; } }
-
 /* Steps */
 .steps { padding: 48px 24px 64px; max-width: 1100px; margin: 0 auto; }
 .steps h2 { text-align: center; font-size: 28px; font-weight: 600; letter-spacing: -1px; margin-bottom: 32px; }
@@ -269,17 +259,6 @@ <h1>Born open, <span class="gradient-text">ship AI together</span>.</h1>
   </div>
 </section>
 
-<a class="bund-banner" href="/bund-summit-2026/">
-  <div class="bund-banner-inner">
-    <div class="bund-banner-text">
-      <span class="bund-tag">外滩大会 2026 · 参赛专区</span>
-      <h2>把你的百炼作品带上外滩大会</h2>
-      <p>用阿里云百炼 CLI、OpenWork、Agent Skills 打造你的参赛作品，一键提交、收录进社区案例库，和开发者社区一起登上外滩大会 2026。</p>
-    </div>
-    <span class="bund-banner-cta">进入专区 &rarr;</span>
-  </div>
-</a>
-
 <section class="steps">
   <h2>三步开始</h2>
   <div class="steps-grid">