Update frontpage.html

build/frontpage.html

@@ -85,9 +85,10 @@
     </div>
   </div>
   <h3> 以及来自社区的 <a href="https://github.com/mli/gluon-tutorials-zh/graphs/contributors">100+ 位贡献者</a></h3>
-  <br>
+  <h3>
   <a class="github-button" href="https://github.com/d2l-ai/d2l-zh" data-icon="octicon-star" data-size="large" data-show-count="true" aria-label="Star d2l-ai/d2l-zh on GitHub">Star</a>
   <a class="github-button" href="https://github.com/d2l-ai/d2l-zh/fork" data-icon="octicon-repo-forked" data-size="large" data-show-count="true" aria-label="Fork d2l-ai/d2l-zh on GitHub">Fork</a>
+  </h3>
 </div>
 
 <div class="endorsement mdl-grid">